Quantification of biomarkers present in dried physiological samples

ABSTRACT

The present disclosure relates to digital immunoassays performed on diluted samples obtained from dried blood spots, for example dried capillary blood samples, to detect the presence or absence of a physiological condition by quantifying one or a combination of biomarkers at concentrations indicative of the condition.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/US2019/026636, filed Apr. 9, 2019, which claims the benefit of U.S. Provisional Application No. 62/789,067, filed Jan. 7, 2019, and U.S. Provisional Application No. 62/655,738, filed Apr. 10, 2018, the disclosure of each of which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to digital immunoassays for quantifying one or more biomarkers present in a dried physiological sample to detect the presence or absence of a physiological condition.

BACKGROUND OF THE INVENTION

Recent advances in digital and spotted well immunoassay technologies are closing in on next-generation capabilities to rapidly diagnosis serious physiological conditions that, even today, frequently go undiagnosed and untreated with potentially tragic consequences. As but one example, these assays have been shown, at least in principle, to quantify subtle changes in biomarkers indicative of neural injuries (for example traumatic brain injury) and neurological disorders (for example multiple sclerosis) at very low concentrations that elude most other assay technologies.

While such developments are promising, most approaches still require physiological fluids such as venous blood or CSF to be collected, preserved, temperature-controlled, and transported within a short period of time. Improved approaches will be needed to achieve a number of important use cases in which patients are especially vulnerable. In an austere environment such as a battlefield, for example, timely transportation of bulk quantities under refrigerated conditions may be logistically infeasible. As another example, venous access to neonates is not always reliable, and in any event only minute, irregular quantities of physiological fluid may be available. More flexible digital immunoassays are needed for use cases such as these.

BRIEF SUMMARY OF THE INVENTION

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury, defect, disorder, or disease) in a subject. In certain embodiments, for example, the test may comprise providing a liquid sample derived from a dried sample of physiological fluid. In certain embodiments, for example, the test may comprise obtaining, via a single multiplex immunoassay (for example a digital multiplex immunoassay or a multiplex spotted well immunoassay), concentrations of at least two analytes in the liquid sample selected from the group consisting of neurofilament light (NF-L), glial fibrillary acidic protein (GFAP), ubiquitin carboxyl-terminal hydrolase L1 (UCH L1), a tau protein (Tau), amyloid beta 40 (A beta 40), amyloid beta 42 (A beta 42), S100 calcium-binding protein B (S100B), and neuron-specific enolase (NSE). In certain embodiments, for example, the test may comprise calculating at least one classification value based on a multivariate classification model using the concentrations as inputs to the multivariate classification model. In certain embodiments, for example, the test may comprise assigning a risk (for example a risk of occurrence or presence) of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the multivariate classification model may be a function of at least two biomarker concentrations, the at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the multivariate classification model may be further a function of at least one demographic parameter (for example age, gender, and/or ethnicity). In certain embodiments, for example, the multivariate classification model may be a logistic regression. In certain embodiments, for example, the multivariate classification model may be a neural network. In certain embodiments, for example, the multivariate classification model may provide a receiver operating characteristic (ROC) curve having an area under the curve (AUC) of at least 0.7 (for example an AUC of at least 0.8 or at least 0.9). In certain embodiments, for example, the multivariate classification model may be characterized by at least one p-value (for example at least one p-value of less than 0.01, less than 0.001, or less than 0.0001).

In certain embodiments, for example, the multivariate classification model may require a baseline concentration of at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE from the subject (for example a baseline concentration obtained from the subject prior to occurrence or suspected occurrence of the neurological condition) as an input to the multivariate classification model. In certain embodiments, for example, the classification value may be based at least on the concentrations of at least three biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, one value of the at least one classification value may comprise a ratio of the concentrations of a first biomarker and a second biomarker determined from the single multiplex immunoassay, the first biomarker and the second biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the at least one classification value may comprise a ratio of the concentration of a first biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE and a second biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

In certain embodiments, for example, the test may further comprise: normalizing one or more of the concentrations based at least on a sample age of the physiological fluid. In certain embodiments, for example, the test may further comprise: normalizing one or more of the concentrations based at least on a sample size of the sample of physiological fluid. In certain embodiments, for example, the test may further comprise: normalizing one or more of the concentrations based at least on sample age of the sample of physiological fluid. In certain embodiments, for example, the test may further comprise: normalizing one or more of the concentrations based at least on one or more demographic characteristics of a subject from which the sample of physiological fluid was taken. In certain embodiments, for example, the one or more demographic characteristics may comprise age. In certain embodiments, for example, the one or more demographic characteristics may comprise ethnicity. In certain embodiments, for example, the one or more demographic characteristics may comprise gender.

B. In certain embodiments, for example, a low risk of the neurological condition may be assigned if the at least one classification value is less than at least one threshold value (for example if the at least one classification value is a plurality of classification values (for example 2 classification values, 3 classification values, 4 classification values, or more than 4 classification values) that have lower values than corresponding threshold values for each of the plurality of classification values). In certain embodiments, for example, the method may further comprise: assigning an indeterminate risk of the neurological condition if one of the at least one classification value exceeds the at least one threshold value.

C. In certain embodiments, for example, the test may further comprise: indicating a neuroimaging study if the at least one classification value is greater than the at least one threshold value. In certain embodiments, for example, the test may further comprise: indicating a neuroimaging study if the at least one classification value is less than the at least one threshold value. In certain embodiments, for example, the test may further comprise: indicating subject observation if the at least one classification value is greater than the at least one threshold value. In certain embodiments, for example, the test may further comprise: indicating subject observation without a neuroimaging study if the at least one classification value is greater than a first value of the at least one threshold value and the at least one classification value is less than a second value of the at least one threshold value. In certain embodiments, for example, the test may further comprise: indicating a change in a course of therapy (for example as an indication of a change in the neurological condition) if the at least one classification value is greater than the at least one threshold value. In certain embodiments, for example, the test may further comprise: indicating a change of therapy treatment (for example as an indication of progress of the neurological condition) if the at least one classification value is less than the at least one threshold value.

D. In certain embodiments, for example, the sample of physiological fluid may be obtained from a subject within 24 hours after a medical procedure is performed on a subject. In certain embodiments, for example, the physiological fluid may be venous blood. In certain embodiments, for example, the sample of physiological fluid may not be used to derive the liquid sample until after an initial diagnosis of the neurological condition. In certain embodiments, for example, the sample of physiological fluid may be taken from a subject while the subject is under continual care of one or more healthcare providers during and following a medical procedure.

E. In certain embodiments, for example, the neurological condition may be a traumatic brain injury. In certain embodiments, for example, the neurological condition may be an acquired brain injury. In certain embodiments, for example, the neurological condition may be collateral to trauma. In certain embodiments, for example, the neurological condition may be collateral to ischemia. In certain embodiments, for example, the neurological condition may be collateral to toxic exposure. In certain embodiments, for example, the neurological condition may be collateral to neurological disease. In certain embodiments, for example, the neurological condition may be collateral to heart attack. In certain embodiments, for example, the neurological condition may be collateral to child birth. In certain embodiments, for example, the neurological condition may be collateral to oxygen deprivation. In certain embodiments, for example, the neurological condition may be collateral to a vehicular accident. In certain embodiments, for example, the neurological condition may be collateral to a fall. In certain embodiments, for example, the neurological condition may be collateral to an assault. In certain embodiments, for example, the neurological condition may be collateral to being struck by an object. In certain embodiments, for example, the neurological condition may be neurodegenerative disease. In certain embodiments, for example, the neurodegenerative disease may be a multiple sclerosis (MS) (for example relapse-remitting MS, primary progressive MS, progressive relapsing MS, and/or secondary progressive MS). In certain embodiments, for example, the neurodegenerative disease may be an Alzheimer's disease.

F. In certain embodiments, for example, the test may be indicated by independent evidence of the neurological condition. In certain embodiments, for example, the test may be indicated by a lawsuit alleging the neurological condition. In certain embodiments, for example, the test may be performed in conjunction with (or indicated by) a positive computerized tomography (CT) scan. In certain embodiments, for example, the test may be performed in conjunction with (or indicated by) a positive MRI scan. In certain embodiments, for example, the test may be performed after an initial diagnosis of the neurological condition.

G. In certain embodiments, for example, the single multiplex immunoassay may be a digital assay. In certain embodiments, for example, the single multiplex immunoassay may be a multiplex spotted well assay.

Certain embodiments may provide, for example, a single-sample test for a neurological condition (for example a traumatic brain injury or MS). In certain embodiments, for example, the single-sample test may comprise providing a liquid sample derived from a single dried sample of physiological fluid from a subject. In certain embodiments, for example, the single-sample test may comprise obtaining, via at least one immunoassay, concentrations of two or more analytes in the liquid sample selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the single-sample test may comprise assigning a risk of the neurological condition in the subject. In certain embodiments, for example, the assigning a risk of the neurological condition in the subject may comprise determining at least one measure of significance of differences between the concentrations of the two or more analytes in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors.

A. In certain embodiments, for example, the subject may be a neonate. In certain embodiments, for example, the subject may be a child. In certain embodiments, for example, the subject may be a toddler. In certain embodiments, for example, the subject may be a teenager. In certain embodiments, for example, the subject may be an adult. In certain embodiments, for example, the subject may be at least 50 years old (for example at least 60 years old, at least 70 years old, or at least 80 years old).

B. In certain embodiments, for example, the single sample of physiological fluid may be obtained within 12 hours of an event suspected of causing the neurological condition in the subject. In certain embodiments, for example, the single sample of physiological fluid may be obtained within 24 hours of an event suspected of causing the neurological condition in the subject.

C. In certain embodiments, for example, the at least one measure of significance of differences may be derived from a classification model (for example a statistical model). In certain embodiments, for example, the classification model may be a function of (or utilize as an input) concentrations for at least one biomarker in the liquid sample and in the group of healthy donors, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the classification model may be further a function of (or utilize as an input) at least one demographic parameter (for example age, gender, and/or ethnicity). In certain embodiments, for example, the classification model may be a logistic regression. In certain embodiments, for example, the classification model may be a neural network. In certain embodiments, for example, the classification model may provide an ROC curve having an AUC of at least 0.7. In certain embodiments, for example, the determining may comprise calculating at least one classification value based on a classification model; and comparing the at least one classification value to at least one threshold value. In certain embodiments, for example, the determining may comprise computing a statistical measure, the statistical measure may comprise a statistic obtained from an analysis of variance (ANOVA). In certain embodiments, for example, the ANOVA may be a one-way ANOVA. In certain embodiments, for example, the ANOVA may be a one-way ANOVA on ranks. In certain embodiments, for example, the ANOVA may be non-parametric. In certain embodiments, for example, the ANOVA may comprise a Kruskal-Wallis test. In certain embodiments, for example, the ANOVA may comprise a Mann-Whitney test. In certain embodiments, for example, the at least one measure of significance of differences may be based on at least three differences between the concentrations of NF-L, GFAP, UCH L1, and Tau in the liquid sample and concentrations of NF-L, GFAP, UCH L1, and Tau in a group of healthy donors.

Certain embodiments may provide, for example, a protocol indicated by potential neurological condition (for example a potential neural injury, potential defect, potential disorder, or potential disease). In certain embodiments, for example, the protocol indicated by the potential neurological condition may comprise a CT scan positive for the neurological condition. In certain embodiments, for example, the protocol may further comprise by one of the single-sample tests for the neurological condition disclosed herein if the CT scan is positive for the neurological condition. In certain embodiments, for example, the protocol may be exclusive of a magnetic resonance imaging (MRI) scan. In certain embodiments, for example, the protocol may be a modification of another protocol to replace an MRI scan with one of the single-sample tests for the neurological condition disclosed herein.

Certain embodiments may provide, for example, a modified protocol indicated by a potential neurological condition. In certain embodiments, for example, the modified protocol indicated by the potential neurological condition may comprise a protocol for detection of a neurological condition comprising a CT scan and in which an MRI scan is replaced by one of the single-sample tests for the neurological condition disclosed herein. In certain embodiments, for example, the at least one immunoassay may be a digital assay. In certain embodiments, for example, the at least one immunoassay may be a multiplex spotted well assay. In certain embodiments, for example, the dried physiological fluid may be derived from venous blood. In certain embodiments, for example, the dried physiological fluid may be a dried serum. In certain embodiments, for example, the dried physiological fluid may be a dried plasma. In certain embodiments, for example, the dried physiological fluid may be dried whole blood. In certain embodiments, for example, the dried physiological fluid may be a dried CSF.

Certain embodiments may provide, for example, a single-assay test for a neurological condition (for example a neural injury, defect, disorder, or disease). In certain embodiments, for example, the single-assay test may comprise providing at least one liquid sample derived from a single dried sample of physiological fluid from a subject. In certain embodiments, for example, the single-assay test may comprise obtaining, via an immunoassay (for example a multiplex immunoassay), concentrations of two or more analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least one liquid sample. In certain embodiments, for example, the single-assay test may comprise assigning a risk of the neurological condition (for example a traumatic brain injury or MS) in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more analytes in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors. In certain embodiments, for example, the immunoassay may be a multiplex digital immunoassay. In certain embodiments, for example, the immunoassay may be a multiplex spotted well assay.

Certain embodiments may provide, for example, a dual-sample test for a neurological condition. In certain embodiments, for example, the dual-sample test may comprise providing, from a subject: a) a first liquid sample derived from a dried sample of a first physiological fluid taken at a first time; and b) a second liquid sample derived from a sample of a second physiological fluid taken at a second time. In certain embodiments, for example, the dual-sample test may comprise obtaining, via immunoassay, concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and in the second liquid sample. In certain embodiments, for example, the dual-sample test may comprise assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the second liquid sample.

A. In certain embodiments, for example, the second time may be later than the first time. In certain embodiments, for example, the first time may be within 3 hours (for example within 6 hours, within 12 hours, within 1 day, or within 7 days) of an event suspected of causing an occurrence of the neurological condition. In certain embodiments, for example, the second time may be at least 2 hours (for example at least 12 hours, at least 1 day, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, or at least 12 days) after the first time. In certain embodiments, for example, the first time may be before an event suspected of causing the neurological condition. In certain embodiments, for example, the second time may be at least 2 hours (for example at least 12 hours, at least 1 day, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, or at least 12 days) after an event suspected of causing an occurrence of the neurological condition.

B. In certain embodiments, for example, the second time may be before the first time. In certain embodiments, for example, the second time may be within 3 hours (for example within 6 hours, within 12 hours, within 1 day, or within 7 days) of an event suspected of causing an occurrence of the neurological condition. In certain embodiments, for example, the first time may be at least 2 hours (for example at least 12 hours, at least 1 day, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, or at least 12 days) after the second time. In certain embodiments, for example, the second time may be before an event suspected of causing the neurological condition. In certain embodiments, for example, the first time may be at least 2 hours (for example at least 12 hours, at least 1 day, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, or at least 12 days) after an event suspected of causing an occurrence of the neurological condition.

Certain embodiments may provide, for example, a dual-sample test for a neurological condition (for example a neural injury, defect, disorder, or disease). In certain embodiments, for example, the dual-sample test may comprise providing, from a subject: a) a first liquid sample derived from a dried first physiological fluid sample taken at a first time; and b) at least a second liquid sample derived from at least a second physiological fluid sample taken at least a second time. In certain embodiments, for example, the dual-sample test may comprise obtaining, via immunoassay, concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and in the at least the second liquid sample. In certain embodiments, for example, the dual-sample test may comprise assigning a risk of the neurological condition (for example a traumatic brain injury or a MS) in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and the concentrations the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least the second liquid sample.

Certain embodiments may provide, for example, a method to distinguish between types of neurological conditions (for example a neural injury, defect, disorder, or disease). In certain embodiments, for example, the method may comprise providing a liquid sample derived from a dried sample of physiological fluid from a subject. In certain embodiments, for example, the method may comprise obtaining, via at least one immunoassay, concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample. In certain embodiments, for example, the method may comprise distinguishing between types of neurological conditions, comprising: a) classifying as statistically significant a difference between at least a first biomarker concentration of the concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors; and b) determining that a difference between at least a second biomarker concentration of the concentrations of two or more of the NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample and concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the group of healthy donors is statistically insignificant.

A. In certain embodiments, for example, the method may distinguish between mild traumatic brain injury and severe traumatic brain injury. In certain embodiments, for example, the at least a first biomarker may comprise GFAP and the at least a first biomarker may be exclusive of NF-L. In certain embodiments, for example, the at least a second biomarker may comprise NF-L.

In certain embodiments, for example, the method may distinguish between a neurological condition arising from isolated contusion (or diffuse axonal injury) and at least one other type of neurological condition. In certain embodiments, for example, the at least a first biomarker may comprise GFAP, UCH L1, and NF-L and may be exclusive of Tau.

In certain embodiments, for example, the method may distinguish between astrocytic injury and neuronal/axonal injury. In certain embodiments, for example, the at least a first biomarker may comprise GFAP. In certain embodiments, for example, the at least a second biomarker may comprise UCH L1 and/or NF-L. In certain embodiments, for example, the method may distinguish between a neurological condition with intracranial hemorrhage and a neurological condition without intracranial hemorrhage. In certain embodiments, for example, the at least a first biomarker may comprise NF-L.

In certain embodiments, for example, the method may distinguish between a first type of MS and a second type of MS. In certain embodiments, for example, the first type of MS and the second type of MS may be selected from the group consisting of relapsing-remitting MS, primary progressive MS, progressive relapsing MS, and secondary progressive MS. In certain embodiments, for example, the at least a first biomarker may comprise GFAP. In certain embodiments, for example, the at least a second biomarker may comprise UCH L1 or NF-L. In certain embodiments, for example, the at least a second biomarker may be at least two biomarkers, the at least two biomarkers comprising UCH L1 and NF-L.

B. In certain embodiments, for example, the at least one difference may be classified using a classification model (for example a statistical model such as a train statistical model). In certain embodiments, for example, the classification model may be a function of (or utilizes as inputs) concentrations for at least one biomarker in the liquid sample and in the group of healthy donor, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, and Tau.

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury, defect, disorder, or disease). In certain embodiments, for example, the test may comprise providing a dried sample of whole blood (for example venous or capillary blood) from a subject. In certain embodiments, for example, the test may comprise eluting the sample with a diluent to form a liquid sample, the diluent comprising a predetermined concentration of at least one heterophilic interference inhibitor for at least one biomarker, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the test may comprise obtaining, via multiplex immunoassay (for example digital immunoassay or multiplex spotted well immunoassay), signal readings for two or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample. In certain embodiments, for example, the test may comprise computing concentrations for the two or more biomarkers in the liquid sample based on a standard curve, the standard curve derived from a plurality of calibration solutions, the calibration solutions exclusive of the heterophilic interference inhibitor.

A. In certain embodiments, for example, the at least one heterophilic interference inhibitor may be configured to increase at least one detectable signal of the immunoassay. In certain embodiments, for example, one of the at least one detectable signal may be associated with NF-L. In certain embodiments, for example, the at least one heterophilic interference inhibitor may comprise an immunoglobulin. In certain embodiments, for example, the immunoglobulin may be a human (or humanized) immunoglobulin. In certain embodiments, for example, the immunoglobulin may be an IgG. In certain embodiments, for example, the immunoglobulin may be a human IgG. In certain embodiments, for example, the at least one heterophilic interference inhibitor may be exclusive of non-human immunoglobulin.

B. In certain embodiments, for example, the sample diluent may comprise phosphate, NaCl, KCl, bovine serum albumin (BSA), MgCl₂, dextrose, bovine gamma globulin (BgG), urea, the non-ionic surfactant sold under the trademark Triton™ X-100, the immunoassay blocker sold under the trademark TRU block™, the heterophile blocking agent sold under the trademark Superchemiblock™, human IgG, the preservative sold under the trademark ProClin™ 300, or a combination of two or more of the foregoing. In certain embodiments, for example, the sample diluent further may comprise 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton™ X-100, 10 mcg/mL TRU block™, 50 mcg/mL Superchemiblock™, 5 mg/mL human IgG, and 0.05% ProClin™ 300.

C. In certain embodiments, for example, the standard curve may be used to compute a spike recovery for at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (for example at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least three of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least four of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least five of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least six of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least seven of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, or each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE) of between 80% and 120% (for example of between 95% and 105%) in the liquid sample (for example when the liquid sample is spiked with NF-L at a concentration of between 5 pg/mL and 1000 pg/mL, for example between 5 pg/mL and 100 pg/mL, between 5 pg/mL and 50 pg/mL, between 5 pg/mL and 10 pg/mL, between 10 pg/mL and 100 pg/mL, between 10 pg/mL and 50 pg/mL, 5 pg/mL 5 pg/mL, 10 pg/mL, 50 pg/mL, 100 pg/mL, or 1000 pg/mL; for example when the liquid sample is spiked with NF-L and GFAP at concentrations of between 5 pg/mL and 1000 pg/mL, for example between 5 pg/mL and 100 pg/mL, between 5 pg/mL and 50 pg/mL, between 5 pg/mL and 10 pg/mL, between 10 pg/mL and 100 pg/mL, between 10 pg/mL and 50 pg/mL, 5 pg/mL 5 pg/mL, 10 pg/mL, 50 pg/mL, 100 pg/mL, or 1000 pg/mL; for example when the liquid sample is spiked with NF-L, GFAP, and Tau at concentrations of between 5 pg/mL and 1000 pg/mL, for example between 5 pg/mL and 100 pg/mL, between 5 pg/mL and 50 pg/mL, between 5 pg/mL and 10 pg/mL, between 10 pg/mL and 100 pg/mL, between 10 pg/mL and 50 pg/mL, 5 pg/mL 5 pg/mL, 10 pg/mL, 50 pg/mL, 100 pg/mL, or 1000 pg/mL; for example when the liquid sample is spiked with the at least one of NF-L, GFAP, Tau, and UCH L1 at a concentrations of between 5 pg/mL and 1000 pg/mL, for example between 5 pg/mL and 100 pg/mL, between 5 pg/mL and 50 pg/mL, between 5 pg/mL and 10 pg/mL, between 10 pg/mL and 100 pg/mL, between 10 pg/mL and 50 pg/mL, 5 pg/mL 5 pg/mL, 10 pg/mL, 50 pg/mL, 100 pg/mL, or 1000 pg/mL; or for example when the liquid sample is spiked with the at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE at a concentration for each of the at least at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE of between 5 pg/mL and 1000 pg/mL, for example between 5 pg/mL and 100 pg/mL, between 5 pg/mL and 50 pg/mL, between 5 pg/mL and 10 pg/mL, between 10 pg/mL and 100 pg/mL, between 10 pg/mL and 50 pg/mL, 5 pg/mL 5 pg/mL, 10 pg/mL, 50 pg/mL, 100 pg/mL, or 1000 pg/mL). In certain embodiments, for example, the standard curve may be used to compute a series of concentrations for at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (for example at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least three of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least four of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least five of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least six of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least seven of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, or each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE) that are between 80% and 140% (for example between 80% and 125% or between 90% and 115%) proportional to one another when the liquid sample (for example a serum sample, plasma sample, or CSF sample) is diluted by between 2 times and 128 times (for example between 4 times and 64 times, such as 4 times, 8 times, 16 times, 32 times, and 64 times diluted) by the sample diluent.

Certain embodiments may provide, for example, an assay indicated by a traumatic event. In certain embodiments, for example, the assay may comprise providing a first liquid sample, the first liquid sample derived from dried first physiological fluid taken from a subject within 24 hours of the event. In certain embodiments, for example, the assay may comprise exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for a plurality of biomarkers, the plurality of biomarkers comprising: at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the assay may comprise binding at least one capture object of the plurality of capture objects to at least one biomarker of the plurality of biomarkers. In certain embodiments, for example, the assay may comprise verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the at least two biomarkers. In certain embodiments, for example, the assay may comprise quantifying first concentrations of the plurality of biomarkers. In certain embodiments, for example, the assay may comprise applying a statistical test to the first concentrations at a p-value of less than 0.05 (for example less than 0.01, 0.001, or 0.0001) to assess a risk of a neurological condition (for example a traumatic brain injury).

A. In certain embodiments, for example, the statistical test may utilize biomarker concentrations obtained for a group of healthy donors as inputs. In certain embodiments, for example, the statistical test may utilize second biomarker concentrations, the second biomarker concentrations quantified from a second liquid sample, the second liquid sample derived from second physiological fluid taken from the subject.

B. In certain embodiments, for example, the second physiological fluid may be taken from the subject at a different time from the time which the first physiological fluid is taken.

C. In certain embodiments, for example, at least one concentration of the first concentrations may be indicative of the neurological condition at a level of less than 1 pmol/L. In certain embodiments, for example, the event may be child birth resulting in a neonate. In certain embodiments, for example, the neonate may be at risk of hypoxia during child birth.

Certain embodiments may provide, for example, a method to detect a neurological condition in a subject. In certain embodiments, for example, the method may comprise performing the assay of indicated by a traumatic event, comprising: i) providing a first liquid sample, the first liquid sample derived from dried first physiological fluid taken from a subject within 24 hours of the event; ii) exposing at least a portion of the first liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for a plurality of biomarkers, the plurality of biomarkers comprising: at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) binding at least one capture object of the plurality of capture objects to at least one biomarker of the plurality of biomarkers; iv) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the at least two biomarkers; and v) quantifying first concentrations of the plurality of biomarkers; and vi) applying a statistical test to the first concentrations at a p-value of less than 0.05 to assess a risk of the neurological condition (for example a traumatic brain injury or MS). In certain embodiments, for example, the method may comprise calculating at least one classification value based on a classification model of the first concentrations. In certain embodiments, for example, the method may comprise assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a method for detecting a neurological condition (for example a traumatic brain injury or MS). In certain embodiments, for example, the method may comprise providing a liquid sample derived from a sample of dried physiological fluid taken from a subject. In certain embodiments, for example, the method may comprise diluting the liquid sample to adjust the liquid sample to within a working range in a digital immunoassay, the working range comprising: a) a plurality of biomarkers comprising at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least one biomarker of the plurality of biomarkers present at a concentration that is greater than a corresponding at least one limit of quantification of the digital immunoassay; and b) at least one threshold indicative of the neurological condition that is greater than the at least one corresponding limit of quantification. In certain embodiments, for example, the method may comprise quantifying concentrations of the at least two biomarkers via the digital immunoassay. In certain embodiments, for example, the digital immunoassay may be a multiplex immunoassay for NF-L, GFAP, UCH L1, and Tau.

Certain embodiments may provide, for example, a method for detecting a neurological condition. In certain embodiments, for example, the method may comprise providing a liquid sample derived from a dried sample of physiological fluid taken from a subject. In certain embodiments, for example, the method may comprise diluting a portion of the liquid sample to align concentrations of at least two biomarkers with a classification model for determining a risk of the neurological condition, the at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the method may comprise quantifying the at least two biomarkers concentrations via a digital immunoassay for NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the classification model may be calibrated to a standard curve.

Certain embodiments may provide, for example, a dual-test method to detect a neurological condition. In certain embodiments, for example, the dual-test method may comprise a first assessment for the neurological condition in a subject. In certain embodiments, for example, the dual-test method may comprise performing, in response to the first assessment, a second assessment for the neurological condition, which second assessment is a multiplex immunoassay for NF-L, GFAP, UCH L1, and Tau on a dried fluid sample derived from the subject. In certain embodiments, for example, the first assessment may comprise a CT scan. In certain embodiments, for example, the first assessment may comprise an MRI scan.

Certain embodiments may provide, for example, a method to screen for a neurological condition. In certain embodiments, for example, the method may comprise providing a liquid sample derived from a dried sample of physiological fluid taken from a subject. In certain embodiments, for example, the method may comprise quantifying a first component in a first portion of the liquid sample. In certain embodiments, for example, the method may comprise computing a dilution factor based on the quantified first component. In certain embodiments, for example, the method may comprise diluting a second portion of the liquid sample by the dilution factor. In certain embodiments, for example, the method may comprise quantifying two or more analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the second portion of the liquid sample. In certain embodiments, for example, the first component concentration may be insensitive to changes in central nervous system (CNS) function associated with onset of one or more neurological conditions.

Certain embodiments may provide, for example, a method to detect a neurological condition. In certain embodiments, for example, the method may comprise: eluting a sample of dried physiological fluid in a diluent to form a diluted sample. In certain embodiments, for example, the method may comprise: performing a multiplex immunoassay on the diluted sample to obtain a plurality of measured parameters. In certain embodiments, for example, the method may comprise: obtaining concentration values for at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, comprising: inputting at least four of the plurality of measured parameters into a multivariate calibration model.

A. In certain embodiments, for example, the diluent may comprise human IgG.

B. In certain embodiments, for example, the multivariate calibration model may be derived from (for example may be fitted to) results of a series of multiplex calibration immunoassays. In certain embodiments, for example, the series of multiplex calibration immunoassays may comprise: i) a first calibration assay performed on a first calibration solution, the first calibration solution comprising NF-L at a first NF-L concentration, GFAP at a first GFAP concentration, UCH L1 at a first UCH L1 concentration, and Tau at a first Tau concentration; and ii) at least a second calibration assay performed on an at least second calibration solution, the at least second calibration solution comprising NF-L at an at least second NF-L concentration, GFAP at an at least second GFAP concentration, UCH L1 at an at least second UCH L1 concentration, and Tau at an at least second Tau concentration. In certain embodiments, for example, the series of multiplex immunoassays may comprise a calibration assay on a calibration solution that is exclusive of NF-L, GFAP, UCH L1, and Tau.

Certain embodiments may provide, for example, a kit. In certain embodiments, for example, the kit may comprise: a plurality of capture agents configured to separately bind to two or more types of analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the kit may comprise: a plurality of detection agents configured to separately bind to the selected two or more types of analytes. In certain embodiments, for example, the kit may comprise: a sample diluent. In certain embodiments, for example, the kit may comprise: at least one calibration solution comprising at least first predetermined concentrations of the selected two or more types of analytes.

A. In certain embodiments, for example, at least one of the plurality of capture agents may comprise a bead (for example a paramagnetic bead configured for use in a multiplex digital immunoassay). In certain embodiments, for example, at least one of the plurality of capture agents may comprise a tag. In certain embodiments, for example, the kit may further comprise at least one bead, the at least one bead configured to selectively bind to the tag.

B. In certain embodiments, for example, the sample diluent may comprise human IgG.

C. In certain embodiments, for example, the at least one calibration solution may be a concentrate. In certain embodiments, for example, the at least one calibration solution may be pre-diluted to a working concentration of one or more of the selected two or more types of analytes.

Certain embodiments may provide, for example, a kit. In certain embodiments, for example, the kit may comprise: a plurality of capture agents configured to separately bind to two or more types of analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the kit may comprise: a plurality of detection agents configured to separately bind to the selected two or more types of analytes. In certain embodiments, for example, the kit may comprise: a sample diluent comprising human IgG. In certain embodiments, for example, the kit may comprise: a plurality of calibration solutions comprising a plurality of predetermined concentrations of the selected two or more types of analytes.

A. In certain embodiments, for example, the human IgG may be present in the sample diluent at a concentration of between 0.1 mg/mL and 25 mg/mL, for example between 0.25 mg/mL and 15 mg/mL, between 0.25 mg/mL and 1.0 mg/mL, between 1 mg/mL and 10 mg/mL, between 1 mg/mL and 3 mg/mL, between 3 mg/mL and 5 mg/mL, between 5 mg/mL and 7 mg/mL, between 7 mg/mL and 9 mg/mL, between 9 mg/mL and 11 mg/mL, between 11 mg/mL and 13 mg/mL, or the human IgG may be present in the diluent at a concentration of between 13 mg/mL and 15 mg/mL. In certain embodiments, for example, the human IgG may be present in the sample diluent at a concentration of 5 mg/mL. In certain embodiments, for example, the human IgG may be present in the sample diluent at a concentration of between 0.1 mcg/mL and 25 mcg/mL, for example between 0.25 mcg/mL and 15 mcg/mL, between 0.25 mcg/mL and 1.0 mcg/mL, between 1 mcg/mL and 10 mcg/mL, between 1 mcg/mL and 3 mcg/mL, between 3 mcg/mL and 5 mcg/mL, between 5 mcg/mL and 7 mcg/mL, between 7 mcg/mL and 9 mcg/mL, between 9 mcg/mL and 11 mcg/mL, between 11 mcg/mL and 13 mcg/mL, or the human IgG may be present in the diluent at a concentration of between 13 mcg/mL and 15 mcg/mL. In certain embodiments, for example, the human IgG may be present in the sample diluent at a concentration of 5 mcg/mL. In certain embodiments, for example, the sample diluent may further comprise at least one heterophile blocking agent exclusive of the human IgG. In certain embodiments, for example, the at least one heterophile blocking agent may be present in the sample diluent at a concentration of at least 1 mcg/mL, for example at least 5 mcg/mL, at least 10 mcg/mL, at least 15 mcg/mL, at least 20 mcg/mL, at least 25 mcg/mL or the at least one heterophile blocking agent may be present in the sample diluent at a concentration of at least 50 mcg/mL. In certain embodiments, for example, the at least one heterophile blocking agent exclusive of human IgG may be present in the sample diluent at a concentration (i.e., the total concentration of all heterophile blocking agents exclusive of human IgG) of between 1 mcg/mL and 100 mcg/mL, for example between 5 mcg/mL and 50 mcg/mL, between 10 mcg/mL and 20 mcg/mL, or the at least one heterophile blocking agent may be present in the sample diluent at a concentration of between 12 mcg/mL and 18 mcg/mL. In certain embodiments, for example, the human IgG may be present in the sample diluent at a concentration of between 1 mg/mL and 10 mg/mL and the at least one heterophile blocking agent exclusive of human IgG may be present at a concentration of at least 10 mcg/mL (for example at least 15 mcg/mL). In certain embodiments, for example, the at least one heterophile blocking agent exclusive of human IgG may be present in the sample diluent at a concentration of 15 mcg/mL. In certain embodiments, for example, the at least one heterophile blocking agent may comprise TRU block™. In certain embodiments, for example, the TRU block™ may be present in the sample diluent at a concentration of between 1 mcg/mL and 100 mcg/mL, for example between 2 mcg/mL and 25 mcg/mL, between 5 mcg/mL and 15 mcg/mL, or the TRU block™ may be present in the sample diluent at a concentration of between 8 mcg/mL and 12 mcg/mL. In certain embodiments, for example, the TRU block™ may be present in the sample diluent at a concentration of 10 mcg/mL. In certain embodiments, for example, the at least one heterophile blocking agent may comprise Superchemiblock™. In certain embodiments, for example, the Superchemiblock™ may be present in the sample diluent at a concentration of between 0.5 mcg/mL and 25 mcg/mL, for example between 1 mcg/mL and 15 mcg/mL, between 2 mcg/mL and 10 mcg/mL, or the Superchemiblock™ may be present in the sample diluent at a concentration of between 3 mcg/mL and 7 mcg/mL. In certain embodiments, for example, the Superchemiblock™ may be present in the sample diluent at a concentration of 5 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of between 1 mg/mL and 10 mg/mL and at least one heterophile blocking agent at a concentration of between 5 and 25 mcg/mL, for example human IgG at a concentration of between 3 mg/mL and 7 mg/mL and at least one heterophile blocking agent at a concentration of between 10 and 20 mcg/mL, human IgG at a concentration of between 3 mg/mL and 7 mg/mL and at least one heterophile blocking agent at a concentration of between 13 and 17 mcg/mL, or human IgG at a concentration of 5 mg/mL and at least one heterophile blocking agent at a concentration of 15 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of between 1 mg/mL and 10 mg/mL, TRU block™ at a concentration of 5 mcg/mL and 15 mcg/mL, and Superchemiblock™ at a concentration of 1 mcg/mL and 10 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of between 3 mg/mL and 7 mg/mL, TRU block™ at a concentration of 5 mcg/mL and 15 mcg/mL, and Superchemiblock™ at a concentration of 1 mcg/mL and 10 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of between 1 mg/mL and 10 mg/mL, TRU block™ at a concentration of 7 mcg/mL and 12 mcg/mL, and Superchemiblock™ at a concentration of 1 mcg/mL and 10 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of between 1 mg/mL and 10 mg/mL, TRU block™ at a concentration of 5 mcg/mL and 15 mcg/mL, and Superchemiblock™ at a concentration of 3 mcg/mL and 7 mcg/mL. In certain embodiments, for example, the sample diluent may comprise human IgG at a concentration of 5 mg/mL, TRU block™ at a concentration of 10 mcg/mL, and Superchemiblock™ at a concentration of 5 mcg/mL. In certain embodiments, for example, the plurality of calibration solutions may be pre-diluted for use to determine a calibration standard curve without further dilution.

B. In certain embodiments, for example, the two or more types of analytes may be four types of analytes consisting of NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the plurality of calibration solutions may be between 6 and 10 calibration solutions, inclusive of an NF-L-free, GFAP-free, UCH L1-free, Tau-free, A beta 40-free, A beta 42-free, S100B-free, and NSE-free control solution. In certain embodiments, for example, the plurality of calibration solutions may comprise: i) a first calibration solution comprising NF-L at a concentration of at least 0.5 pg/mL, GFAP at a concentration of at least 1 pg/mL, UCH L1 at a concentration of at least 10 pg/mL, and Tau at a concentration of at least 0.1 pg/mL; ii) a second calibration solution comprising NF-L at a concentration of at least 450 pg/mL, GFAP at a concentration of at least 900 pg/mL, UCH L1 at a concentration of at least 9000 pg/mL, and Tau at a concentration of at least 90 pg/mL; and iii) at least a third calibration solution comprising NF-L at a concentration of between 10 pg/mL and 450 pg/mL, GFAP at a concentration of between 20 pg/mL and 900 pg/mL, UCH L1 at a concentration of between 200 pg/mL and 9000 pg/mL, and Tau at a concentration of between 2 pg/mL and 90 pg/mL.

C. In certain embodiments, for example, at least one of the plurality of capture agents may comprise a paramagnetic bead configured for use in a multiplex digital immunoassay analyzer. In certain embodiments, for example, the kit may be configured to prepare a sample for assay by a multiplex spotted well immunoassay. In certain embodiments, for example, the plurality of detection agents may comprise: i) an NF-L detection agent configured to bind to NF-L; and ii) at least one of a GFAP detection agent configured to bind to GFAP, a UCH L1 detection agent configured to bind to UCH L1, a Tau detection agent configured to bind to Tau, an A beta 40 detection agent configured to bind to A beta 40, an A beta 42 detection agent configured to bind to A beta 42, an S100B detection agent configured to bind to S100B, and an NSE detection agent configured to bind to NSE.

Certain embodiments may provide, for example, a method to detect a neurological condition. In certain embodiments, for example, the method may comprise: diluting a sample of dried physiological fluid in a diluent to form a diluted sample. In certain embodiments, for example, the method may comprise: performing a multiplex immunoassay on the diluted sample to obtain a plurality of measured parameters. In certain embodiments, for example, the method may comprise: obtaining concentration values for at least two analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, comprising: inputting at least two of the plurality of measured parameters into a multivariate calibration model.

A. In certain embodiments, for example, the measured parameters may comprise signal readings from a multiplex spotted well immunoassay. In certain embodiments, for example, the measured parameters may be derived from Poisson and/or Gaussian distribution analysis of results of a digital immunoassay.

B. In certain embodiments, for example, the multivariate calibration model may be derived from a results of a series of multiplex calibration immunoassays. In certain embodiments, for example, the multivariate calibration model may be derived from one or more polynomial regressions using the results as inputs. In certain embodiments, for example, the multivariate calibration model may have R² values of at least 0.95 for at least two of: i) NF-L at a concentration of between 1 pg/mL and 50 pg/mL; ii) Tau at a concentration of between 0.1 pg/mL and 8 pg/mL; iii) GFAP at a concentration of between 5 pg/mL and 100 pg/mL; iv) UCH L1 at a concentration of between 20 pg/mL and 500 pg/mL; v) A beta 40 at a concentration of between 10 pg/mL and 100 pg/mL; vi) A beta 42 at a concentration of between 10 pg/mL and 100 pg/mL; vii) S100B at a concentration of between 10 pg/mL and 100 pg/mL; and viii) NSE at a concentration of between 10 pg/mL and 100 pg/mL. In certain embodiments, for example, the multivariate calibration model may have R² values of at least 0.95 for at least two of: i) NF-L at a concentration of between 0.1 pg/mL and 10 pg/mL; ii) Tau at a concentration of between 0.1 pg/mL and 8 pg/mL; iii) GFAP at a concentration of between 10 pg/mL and 500 pg/mL; iv) UCH L1 at a concentration of between 20 pg/mL and 100 pg/mL; v) A beta 40 at a concentration of between 10 pg/mL and 100 pg/mL; vi) A beta 42 at a concentration of between 10 pg/mL and 100 pg/mL; vii) S100B at a concentration of between 10 pg/mL and 100 pg/mL; and viii) NSE at a concentration of between 10 pg/mL and 100 pg/mL.

C. In certain embodiments, for example, the series of multiplex calibration immunoassays may comprise: i) a first calibration assay performed on a first calibration solution, the first calibration solution comprising NF-L at a first NF-L concentration, GFAP at a first GFAP concentration, UCH L1 at a first UCH L1 concentration, Tau at a first Tau concentration, A beta 40 at a first A beta 40 concentration, A beta 42 at a first A beta 42 concentration, S100B at a first S100B concentration, and NSE at a first NSE concentration; and ii) at least a second calibration assay performed on an at least second calibration solution, the at least second calibration solution comprising NF-L at an at least second NF-L concentration, GFAP at an at least second GFAP concentration, UCH L1 at an at least second UCH L1 concentration, Tau at an at least second Tau concentration, A beta 40 at an at least second A beta 40 concentration, A beta 42 at an at least second A beta 42 concentration, S100B at an at least second S100B concentration, and NSE at an at least second NSE concentration.

D. In certain embodiments, for example, a comparative series of multiplex immunoassays for NF-L, GFAP, UCH L1, and Tau may be performed to obtain a series of comparative measured parameters (for example signal readings or digital assay results) corresponding to at least one of NF-L, GFAP, Tau, and UCH L1 (for example at least two of NF-L, GFAP, Tau, and UCH L1, at least three of NF-L, GFAP, Tau, and UCH L1, or each of NF-L, GFAP, Tau, and UCH L1) that are between 80% and 140% (for example between 80% and 125% or between 90% and 115%) proportional to one another when the sample of physiological fluid (for example a serum sample, plasma sample, or CSF sample) is diluted by between 2 times and 128 times (for example between 4 times and 64 times, such as 4 times, 8 times, 16 times, 32 times, and 64 times diluted) by the sample diluent. In certain embodiments, for example, the multivariate calibration model may be used to obtain a series of comparative concentration values for at least one of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (for example at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least three of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least four of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least five of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, at least six of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, or each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE) that are between 80% and 140% (for example between 80% and 125% or between 90% and 115%) proportional to one another when the sample of physiological fluid (for example a serum sample, plasma sample, or CSF sample) is diluted by between 2 times and 128 times (for example between 4 times and 64 times, such as 4 times, 8 times, 16 times, 32 times, and 64 times diluted) by the sample diluent. In certain embodiments, for example, the diluent may comprise between 1 mg/mL and 50 mg/mL human IgG (for example between 1 mg/mL and 10 mg/mL, between 3 mg/mL and 7 mg/mL, or 5 mg/mL human IgG).

Certain embodiments may provide, for example, a test for a neurological condition. In certain embodiments, for example, the test may comprise: providing a liquid sample derived from a dried sample of physiological fluid. In certain embodiments, for example, the test may comprise: obtaining, via a multiplex immunoassay, concentrations of at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample. In certain embodiments, for example, the test may comprise: calculating at least one classification value based on a multivariate classification model using the concentrations as inputs to the multivariate classification model. In certain embodiments, for example, the test may comprise: assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the multivariate classification model may predict traumatic brain injury with an ROC curve having an AUC of at least 0.85. In certain embodiments, for example, the multivariate classification model may predict a traumatic brain injury with a true positive rate of at least 75% at a false positive rate of less than 25%.

B. In certain embodiments, for example, the test may further comprise: obtaining a CT scan result negative for the neurological condition prior to performing the multiplex immunoassay. In certain embodiments, for example, the multivariate classification model may comprise a neural network.

Certain embodiments may provide, for example, a test for a neurological condition, comprising: i) providing a liquid sample derived from a sample of physiological fluid; ii) obtaining, via a single multiplex immunoassay, concentrations of at least two analytes in the liquid sample selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) calculating at least one classification value based on a multivariate classification model using the concentrations as inputs to the multivariate classification model; and iv) assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a single-sample test for a neurological condition, comprising: i) providing a liquid sample derived from a single dried sample of physiological fluid from a subject; ii) obtaining, via at least one immunoassay, concentrations of two or more analytes in the liquid sample selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; and iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more analytes in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors.

Certain embodiments may provide, for example, a protocol indicated by a potential neurological condition, comprising a CT scan positive for a neurological condition; followed by one of the single-sample tests for the neurological condition disclosed herein.

Certain embodiments may provide, for example, a modified protocol indicated by a potential neurological condition, comprising a protocol for detection of the neurological condition comprising a CT scan and in which an MRI scan is replaced by one of the single-sample tests for the neurological condition disclosed herein.

Certain embodiments may provide, for example, a single-assay test for a neurological condition, comprising: i) providing at least one liquid sample derived from a single dried sample of physiological fluid from a subject; ii) obtaining, via an immunoassay, concentrations of two or more analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least one liquid sample; and iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more analytes in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors.

Certain embodiments may provide, for example, a dual-sample test for a neurological condition, comprising: i) providing, from a subject: a) a first liquid sample derived from a sample of a first dried physiological fluid taken at a first time; and b) a second liquid sample derived from a sample of a second physiological fluid taken at a second time; ii) obtaining, via immunoassay, concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and in the second liquid sample; iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the second liquid sample.

Certain embodiments may provide, for example, a dual-sample test for a neurological condition, comprising: i) providing, from a subject: a) a first liquid sample derived from a dried first physiological fluid sample taken at a first time; and b) at least a second liquid sample derived from at least a second physiological fluid sample taken at least a second time; ii) obtaining, via immunoassay, concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and in the at least the second liquid sample; iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample and the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least the second liquid sample.

Certain embodiments may provide, for example, a method to distinguish between types of neurological condition, comprising: i) providing a liquid sample derived from a dried sample of physiological fluid from a subject; ii) obtaining, via at least one immunoassay, concentrations of NF-L, GFAP, UCH L1, and Tau in the liquid sample; iii) distinguishing between types of neurological condition, comprising: a) classifying as statistically significant a difference between at least a first biomarker concentration of the concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample and concentrations of two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in a group of healthy donors; and b) determining that a difference between at least a second biomarker concentration of the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample and the concentrations of the two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the group of healthy donors is statistically insignificant.

Certain embodiments may provide, for example, a test for a neurological condition, comprising i) providing a dried sample of whole blood (for example venous blood or capillary blood) from a subject; ii) eluting the sample with a diluent to form a liquid sample, the diluent comprising a predetermined concentration of at least one heterophilic interference inhibitor for at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) obtaining, via multiplex immunoassay, signal readings for two or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample; and iii) computing concentrations for the two or more biomarkers in the liquid sample based on a standard curve, the standard curve derived from a plurality of calibration solutions, the calibration solutions exclusive of the heterophilic interference inhibitor.

Certain embodiments may provide, for example, an assay indicated by a traumatic event, comprising: i) providing a first liquid sample, the first liquid sample derived from dried first physiological fluid taken from a subject within 24 hours of the event; ii) exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for a plurality of biomarkers, the plurality of biomarkers comprising: at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) binding at least one capture object of the plurality of capture objects to at least one biomarker of the plurality of biomarkers; iv) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the at least two biomarkers; v) quantifying first concentrations of the plurality of biomarkers; and vi) applying a statistical test to the first concentrations at a p-value of less than 0.05 to assess a risk of a neurological condition.

Certain embodiments may provide, for example, a method to detect a neurological condition in a subject, comprising: i) performing an assay indicated by a traumatic event, comprising: a) providing a first liquid sample, the first liquid sample derived from dried first physiological fluid taken from a subject within 24 hours of the event; b) exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for a plurality of biomarkers, the plurality of biomarkers comprising: at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; c) binding at least one capture object of the plurality of capture objects to at least one biomarker of the plurality of biomarkers; d) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the at least two biomarkers; and e) quantifying first concentrations of the plurality of biomarkers; and f) applying a statistical test to the first concentrations at a p-value of less than 0.05 to assess a risk of a neurological condition; ii) calculating at least one classification value based on a classification model of the first concentrations; and iii) assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a method for detecting a neurological condition, comprising: i) providing a liquid sample derived from a sample of dried physiological fluid taken from a subject; ii) diluting the liquid sample to adjust the liquid sample to within a working range in a digital immunoassay, the working range comprising: a) a plurality of biomarkers comprising NF-L, GFAP, UCH L1, and Tau, at least one biomarker of the plurality of biomarkers present at a concentration that is greater than a corresponding at least one limit of quantification of the digital immunoassay; and b) at least one threshold indicative of the neurological condition that is greater than the at least one corresponding limit of quantification; and iii) quantifying concentrations NF-L, GFAP, UCH L1, and Tau via the digital immunoassay.

Certain embodiments may provide, for example, a method for detecting a neurological condition, comprising: i) providing a liquid sample derived from a sample of dried physiological fluid taken from a subject; ii) diluting a portion of the liquid sample to align concentrations of at least two biomarkers with a classification model for determining a risk of the neurological condition, the at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, and Tau; and iii) quantifying the at least two biomarkers concentrations via a digital immunoassay for NF-L, GFAP, UCH L1, and Tau.

Certain embodiments may provide, for example, a dual-test method to detect a neurological condition, comprising: i) a first assessment for the neurological condition in a subject; and ii) performing, in response to the first assessment, a second assessment for the neurological condition, which second assessment is a multiplex immunoassay for at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE on a fluid sample derived from the subject.

Certain embodiments may provide, for example, a method to screen for a neurological condition, comprising: i) providing a liquid sample derived from a sample of dried physiological fluid taken from a subject; ii) quantifying a first component in a first portion of the liquid sample; iii) computing a dilution factor based on the quantified first component; iv) diluting a second portion of the liquid sample by the dilution factor; and v) quantifying at least two analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the second portion of the liquid sample.

Certain embodiments may provide, for example, a method to detect a neurological condition, comprising: i) eluting a sample of dried physiological fluid in a diluent to form a diluted sample; ii) performing a multiplex immunoassay on the diluted sample to obtain a plurality of measured parameters; and iii) obtaining concentration values for at least four analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, comprising: inputting at least four of the plurality of measured parameters into a multivariate calibration model.

Certain embodiments may provide, for example, a kit, comprising: i) a plurality of capture agents configured to separately bind to two or more types of analytes selected from the group consisting of NF-L, GFAP, UCH L1, and Tau; ii) a plurality of detection agents configured to separately bind to the selected two or more types of analytes; iii) a sample diluent; and iv) at least one calibration solution comprising at least first predetermined concentrations of the selected two or more types of analytes.

Certain embodiments may provide, for example, a kit, comprising: i) a plurality of capture agents configured to separately bind to two or more types of analytes selected from the group consisting of NF-L, GFAP, UCH L1, and Tau; ii) a plurality of detection agents configured to separately bind to the selected two or more types of analytes; iii) a sample diluent comprising human IgG; and iv) plurality of calibration solutions comprising a plurality of predetermined concentrations of the selected two or more types of analytes.

Certain embodiments may provide, for example, a method to detect a neurological condition, comprising: i) diluting a sample of physiological fluid in a diluent to form a diluted sample; ii) performing a multiplex immunoassay on the diluted sample to obtain a plurality of measured parameters; and iii) obtaining concentration values for at least two analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, comprising: inputting at least four of the plurality of measured parameters into a multivariate calibration model.

Certain embodiments may provide, for example, a test for a neurological condition, comprising: i) providing a liquid sample derived from a dried sample of physiological fluid; ii) obtaining, via a multiplex immunoassay, concentrations of NF-L, GFAP, UCH L1, and Tau in the liquid sample; iii) calculating at least one classification value based on a multivariate classification model using the concentrations as inputs to the multivariate classification model; and iv) assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

Methods and kits for determining a measure of the concentration of a panel neurological biomarkers in a sample derived from a patient are generally provided.

The subject matter of the present invention involves, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of one or more systems and/or articles.

In certain embodiments, for example (for example in one set of embodiments), the methods, tests, assays, kits, or systems (for example methods) may comprise determining a measure of the concentration of a panel of biomarkers in a sample, comprising performing an assay on a sample derived from a human and determining a measure of the concentration of NF-L and at least one other biomarker selected from the group consisting of GFAP, UCH L1, and Tau, in the sample collected from the patient. Certain embodiments, for example, may provide an assay having an LOQ of no greater than 0.1 pg/mL for Tau protein, no greater than 1 pg/mL for NF-L and GFAP, and no greater than 5 pg/mL for UCH L1.

In certain embodiments, for example (for example in another set of embodiments), the methods, tests, assays, kits, or systems (for example kits) may be used for determining a measure of the concentration of a panel of biomarkers in a sample comprises a plurality of capture objects, each having a binding surface comprising a plurality of capture components, a plurality of a first type of binding ligand having affinity for NF-L, and a plurality of a second type of binding ligand and a third type of binding ligand having affinity for at least two other biomarkers selected from the group consisting of GFAP, UCH L1, and Tau.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems to quantify abnormally high (or abnormally depressed) levels of one or more biomarkers (for example a panel of biomarkers) indicative of a neurological condition (for example a neural injury) in a subject. In certain embodiments, for example, the one or more biomarkers may be obtained from dried physiological fluid (for example from a dried blood spot of venous or capillary blood). In certain embodiments, for example, the dried physiological fluid may be limited to a single sample (for example a single sample of dried blood obtained from the subject proximate the neural injury). In certain embodiments, for example, the dried physiological fluid may be at least 2 months old (for example between 2 months and 5 years old). In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise detecting at least one of the one or more biomarkers at a molar concentration of less than 1 picomole/L. In certain embodiments, for example, concentrations of the one or more biomarkers may be determined in a series of assays performed on samples of dried physiological fluids taken from the subject at different times. In certain embodiments, for example, results from the series of assays may be used for diagnosis, prognosis, or monitoring to determine whether a condition resulting from the neurological condition (for example neural injury) is improving or worsening.

Certain embodiments may provide, for example, an assay indicated by a traumatic event. In certain embodiments, for example, the assay may comprise: providing a liquid sample, the liquid sample derived from a dried sample of physiological fluid (for example a dried blood spot of capillary blood present on filter paper) taken within 24 hours of the event. In certain embodiments, for example, the assay may comprise: exposing at least a portion of the liquid sample to a plurality of capture objects (for example paramagnetic beads conjugated with anti-biomarker immobilization agents or one of the capture objects disclosed herein or in one of the INCORPORATED REFERENCES), the plurality of capture objects comprising binding surfaces having affinity for one or more biomarkers. In certain embodiments, for example, the assay may comprise: binding at least one capture object of the plurality of capture objects to at least one biomarker of the one or more biomarkers; iv) verifying that a statistically significant proportion (for example at least 10%, at least 20%, at least 30%, or at least 45%) of the exposed plurality of capture objects are not bound to any of the one or more biomarkers. In certain embodiments, for example, the assay may comprise: quantifying concentrations of the one or more biomarkers, at least one of the concentrations indicative of a neurological condition (for example a neural injury) at a level of less than 1 picomole/L.

A. In certain embodiments, for example, the one or more biomarkers may comprise one or more of the biomarkers disclosed herein or in one of the INCORPORATED REFERENCES. In certain embodiments, for example, the one or more biomarkers may comprise a neurofilament. In certain embodiments, for example, the neurofilaments may be a type IV intermediate filaments or heteropolymers. In certain embodiments, for example, the neurofilament may be selected from the group consisting of neurofilament heavy chain (NF-H), neurofilament medium chain (NF-M), NF-L, α-internexin, and peripherin. In certain embodiments, for example, the one or more biomarkers may comprise NF-L. In certain embodiments, for example, the one or more biomarkers may comprise GFAP. In certain embodiments, for example, the one or more biomarkers may comprise UCH L1. In certain embodiments, for example, the one or more biomarkers may comprise a tau protein (Tau), for example one isoform of tau protein, 2 isoforms of tau protein, 3 isoforms of tau protein, 4 isoforms of tau protein, 5 isoforms of tau protein, 6 isoforms of tau protein, or a phosphorylated tau protein (for example p-tau-81 or p-tau-231). In certain embodiments, for example, the tau protein may comprise tau 23. In certain embodiments, for example, the tau protein may comprise tau 24. In certain embodiments, for example, the tau protein may comprise tau 37. In certain embodiments, for example, the tau protein may comprise tau 34. In certain embodiments, for example, the tau protein may comprise tau 39. In certain embodiments, for example, the tau protein may comprise tau 40. In certain embodiments, for example, the tau protein may be phosphorylated. In certain embodiments, for example, the one or more biomarkers may comprise a beta-amyloid precursor protein. In certain embodiments, for example, the one or more biomarkers may comprise a protein derived from amyloid beta precursor protein (for example a proteolytic product of amyloid beta precursor protein). In certain embodiments, for example, the one or more biomarkers may comprise A beta 40. In certain embodiments, for example, the one or more biomarkers may comprise A beta 42. In certain embodiments, for example, the one or more biomarkers may comprise S100B. In certain embodiments, for example, the one or more biomarkers may comprise NSE. In certain embodiments, for example, the one or more biomarkers may comprise β-site aPP-cleaving enzyme 1 (BACe1). In certain embodiments, for example, the one or more biomarkers may comprise myelin basic protein (MBP). In certain embodiments, for example, the one or more biomarkers may comprise growth associated protein 43. In certain embodiments, for example, the one or more biomarkers may comprise glutamine synthetase. In certain embodiments, for example, the one or more biomarkers may comprise a glycine transporter (for example at least one of GLYT1 and GLYT2). In certain embodiments, for example, the one or more biomarkers may comprise a neuron specific glycoprotein (for example GP50). In certain embodiments, for example, the one or more biomarkers may comprise calpain. In certain embodiments, for example, the one or more biomarkers may comprise heat shock protein 72. In certain embodiments, for example, the one or more biomarkers may comprise calbindin D-28K. In certain embodiments, for example, the one or more biomarkers may comprise a proteolipid protein. In certain embodiments, for example, the one or more biomarkers may comprise a myeline associated glycoprotein. In certain embodiments, for example, the one or more biomarkers may comprise a creatine kinase protein (for example CK-BB). In certain embodiments, for example, the one or more biomarkers may comprise an endothelium membrane protein (for example thrombomodulin). In certain embodiments, for example, the one or more biomarkers may comprise a combination of two or more of the foregoing biomarkers. In certain embodiments, for example, the one or biomarkers may be NF-L. In certain embodiments, for example, the one or biomarkers may be GFAP. In certain embodiments, for example, the one or biomarkers may be Tau. In certain embodiments, for example, the one or biomarkers may comprise NF-L, GFAP, and Tau, exclusive of UCH L1. In certain embodiments, for example, the one or biomarkers may comprise NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the one or biomarkers may comprise NF-L, GFAP, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the one or biomarkers may comprise, NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the one or biomarkers may be exclusive of UCH L1. In certain embodiments, for example, the one or more biomarkers may be exclusive of NF-L.

B. In certain embodiments, for example, the neurological condition (for example neural injury) may comprise a traumatic brain injury (for example a brain injury in a newborn resulting from birth of the newborn). In certain embodiments, for example, the neurological condition (for example neural injury) may comprise an acquired brain injury. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to trauma. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to ischemia. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to toxic exposure. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to neurological disease. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to heart attack. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to child birth. In certain embodiments, for example, the neurological condition (for example neural injury) may be collateral to oxygen deprivation.

C. In certain embodiments, for example, the dried sample may comprise a dried blood spot. In certain embodiments, for example, the dried sample may be obtained from a heel prick (i.e., a liquid sample may be obtained by the heel prick and then dried). In certain embodiments, for example, the dried sample may be obtained from a finger prick. In certain embodiments, for example, the dried sample may be obtained from a neonate.

D. In certain embodiments, for example, the assay may be performed at least 2 months (for example at least 6 months, at least 1 year, at least 2 years, at least 5 years, or between 2 months and 5 years) after the event. In certain embodiments, for example, the assay may be further indicated by independent evidence of neural injury. In certain embodiments, for example, the assay may be further indicated by a lawsuit alleging neural injury.

E. In certain embodiments, for example, the event may comprise child birth resulting in a neonate. In certain embodiments, for example, the neonate may be at risk of hypoxia during child birth. In certain embodiments, for example, the sample of dried physiological fluid may be obtained from the neonate within 12 hours of the child birth.

F. In certain embodiments, for example, the liquid sample may be derived from a supernatant liquid. In certain embodiments, for example, the liquid sample may be derived from an elution product of the dried sample.

G. In certain embodiments, for example, dried sample may comprise dried capillary blood. In certain embodiments, for example, the dried sample may be obtained from a subject within 20 hours after a medical procedure is performed on a subject. In certain embodiments, for example, the dried sample may weigh less than 25 mg.

Certain embodiments may provide, for example, a method to detect a neurological condition (for example a neural injury) in a subject. In certain embodiments, for example, the method may comprise: performing one of the assays (for example the foregoing assay) disclosed herein. In certain embodiments, for example, the method may comprise: calculating at least one classification value based on a classification model of the concentrations of the one or more biomarkers. In certain embodiments, for example, the method may comprise: assigning a risk of the neurological condition (for example neural injury) (and optionally prescribing an indicated neurological test), comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, a neuroimaging study may be indicated if the at least one classification value is greater than the at least one threshold value. In certain embodiments, for example, a neuroimaging study may not be indicated if the at least one classification value is less than the at least one threshold value. In certain embodiments, for example, subject observation may be indicated if the at least one classification value is greater than the at least one threshold value. In certain embodiments, for example, subject observation without a neuroimaging study may be indicated if the at least one classification value is greater than a first value of the at least one threshold value and the at least one classification value is less than a second value of the at least one threshold value.

B. In certain embodiments, for example, the classification model may require a baseline concentration of at least one of the one or more biomarkers from the subject.

Certain embodiments may provide, for example, a method to determine when a neural injury occurred. In certain embodiments, for example, the method may comprise: providing a liquid sample derived from a dried sample comprising physiological fluid (for example a liquid sample comprising an elution product of the dried sample or a supernatant fluid obtained from the dried sample), wherein the dried sample is at least 2 months old (for example a 2 month old sample of capillary blood taken from a subject and immediately air-dried under ambient conditions). In certain embodiments, for example, the method may comprise: quantifying at least one parameter for at least one biomarker in the liquid sample, the at least one biomarker (for example a concentration of NF-L and/or GFAP) indicative of the neural injury at a concentration in the liquid sample of less than 1 picomole/L.

A. In certain embodiments, for example, the method may be performed after an initial diagnosis of the neural injury.

B. In certain embodiments, for example, the dried sample may not be tested (for example the liquid sample may not be derived) until after an initial diagnosis of the neural injury. In certain embodiments, for example, the dried sample may be taken from a subject before a further sample is taken from the subject, the further sample used in an initial diagnosis of the neural injury.

C. In certain embodiments, for example, the least one biomarker may comprise NF-L. In certain embodiments, for example, the at least one biomarker may comprise GFAP. In certain embodiments, for example, the at least one biomarker may comprise UCH L1. In certain embodiments, for example, the at least one biomarker may comprise tau protein (Tau). In certain embodiments, for example, the at least one biomarker may comprise A beta 40. In certain embodiments, for example, the at least one biomarker may comprise A beta 42. In certain embodiments, for example, the at least one biomarker may comprise S100B. In certain embodiments, for example, the at least one biomarker may comprise NSE. In certain embodiments, for example, the at least one biomarker concentration may be quantified via a digital immunoassay. In certain embodiments, for example, the at least one biomarker may be indicative of a neural injury during a time interval of between 2 hours and 120 hours prior to a date on which the physiological fluid was taken from a subject.

D. In certain embodiments, for example, the at least one parameter may comprise a relative concentration of a first biomarker of the at least one biomarker. In certain embodiments, for example, the relative concentration of the first biomarker may be a ratio of a concentration of the first biomarker to a concentration of a second component of the liquid sample. In certain embodiments, for example, the at least one biomarker may be at least two biomarkers, and the relative concentration of the first biomarker may be a ratio of the concentration of the first biomarker to a concentration of a second biomarker of the at least two biomarkers. In certain embodiments, for example, the ratio may be at least 0.01 (for example at least 0.1, at least 0.2, at least 0.5, at least 1, at least 2, at least 5, at least 10, or at least 100). In certain embodiments, for example, the at least one parameter may comprise a normalized concentration of a first biomarker of the at least one biomarker. In certain embodiments, for example, the normalized concentration may be a normalized protein expression (NPX) value. In certain embodiments, for example, the at least one biomarker may be at least two biomarkers, and the at least one parameter may comprise a sum of a concentration of a first biomarker of the at least two biomarkers and a concentration of a second biomarker of the at least two biomarkers.

Certain embodiments may provide, for example, a single-sample test for a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the single-sample test may comprise: providing a liquid sample derived from a single sample of dried capillary blood. In certain embodiments, for example, the single-sample test may comprise: obtaining, via digital immunoassay (for example a Simoa Multiplex Neurology 4-Plex “A” (N4PA) Assay run on a Quanterix HD-1 Analyzer or one of the other digital immunoassays disclosed herein or in one of the INCORPORATED REFERENCES), a concentration in the liquid sample of NF-L (or another biomarker, for example GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, or NSE). In certain embodiments, for example, the single-sample test may comprise: calculating at least one classification value based on a classification model of the concentration. In certain embodiments, for example, the single-sample test may comprise: assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the digital immunoassay may comprise a multiplex digital immunoassay.

B. In certain embodiments, for example, the obtaining may further comprise obtaining at least one concentration of at least one additional biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (or another biomarker disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the classification value may be based on the concentration of NF-L and the at least one concentration of the at least one additional biomarker. In certain embodiments, for example, the at least one classification value may comprise a ratio of the concentration of NF-L and one of the at least one concentration of the at least one additional biomarker.

C. In certain embodiments, for example, the single sample of dried capillary blood may be taken from a subject at a sample time of between 1 hours and 10 hours following one or more of trauma, ischemia, a medical procedure, and toxic exposure.

D. In certain embodiments, for example, the at least one classification value may comprise a ratio of one of the concentration to a concentration of a reference component present in the liquid sample.

E. In certain embodiments, for example, the test may further comprise: normalizing the concentration based at least on a sample size of the single sample of dried physiological fluid. In certain embodiments, for example, the test may further comprise: normalizing the concentration based at least on sample age of the single sample of dried physiological fluid.

F. In certain embodiments, for example, the test may further comprise: normalizing the concentration based at least on one or more demographic characteristics of a subject from which the physiological fluid was taken. In certain embodiments, for example, the one or more demographic characteristics may comprise age. In certain embodiments, for example, the one or more demographic characteristics may comprise ethnicity.

Certain embodiments may provide, for example, a single-sample test for excluding a neurological condition (for example a neural injury or a degenerative neurological disease) as a result of a medical procedure. In certain embodiments, for example, the single-sample test may comprise: providing a liquid sample derived from a single sample of dried physiological fluid, the single sample of dried physiological fluid obtained from a subject after a medical procedure is performed on the subject. In certain embodiments, for example, the single-sample test may comprise: obtaining, via digital immunoassay of at least a portion of the liquid sample, a concentration of NF-L (or another biomarker, for example GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, or NSE). In certain embodiments, for example, the single-sample test may comprise: calculating at least one classification value for the subject based on a classification model of the concentration. In certain embodiments, for example, the single-sample test may comprise: assigning a low risk of the neurological condition (for example a neural injury or a degenerative neurological disease) if the at least one classification value is less than at least one threshold value.

A. In certain embodiments, for example, the single sample may be taken while the subject is under continual care of one or more healthcare providers during and following the medical procedure. In certain embodiments, for example, the single-sample test may further comprise: assigning an indeterminate risk of the neurological condition (for example a neural injury or a degenerative neurological disease) if the at least one classification value exceeds the at least one threshold value.

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the test may comprise: providing at least one liquid sample derived from at least one sample of dried capillary blood, the at least one sample of dried capillary blood obtained from a subject during a 10-hour time window (or another time window such as a less than 48-hour time window, less than 24-hour time window, less than 12-hour time window, less than 10-hour time window, less than 6-hour time window, or less than 1-hour time window). In certain embodiments, for example, the test may comprise: obtaining, via at least one digital immunoassay of at least a portion of the at least one liquid sample, a concentration of NF-L (or another biomarker, for example GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, or NSE). In certain embodiments, for example, the test may comprise: calculating at least one classification value for the subject based on a classification model of the concentration. In certain embodiments, for example, the test may comprise: assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the 10-hour time window (or another time window such as a less than 48-hour time window, less than 24-hour time window, less than 12-hour time window, less than 10-hour time window, or less than 6-hour time window, or less than 1 hour time window) may begin within 1 hour (or may begin within 30 minutes, or within 2 hours) of a medical procedure.

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the test may comprise: providing a liquid sample derived from a sample of dried physiological fluid from a subject. In certain embodiments, for example, the test may comprise: obtaining, via a digital immunoassay of at least a portion of the liquid sample, a concentration for at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (or the group consisting of GFAP, Tau, A beta 40, A beta 42, S100B, and NSE, exclusive of NF-L and/or UCH L1). In certain embodiments, for example, the test may comprise: normalizing the concentration based at least on a sample age (for example a sample age based on how long the sample has been stored) of the dried physiological fluid. In certain embodiments, for example, the test may comprise: normalizing the concentration based at least on sample storage conditions (for example average temperature and/or relative humidity, or maximum temperature and/or relative humidity) of the dried physiological fluid. In certain embodiments, for example, the test may comprise: calculating at least one classification value for the subject based on a classification model of the normalized concentration. In certain embodiments, for example, the test may comprise: assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the test may further comprise: further normalizing the at least one concentration based on at least one sample size (for example a tared weight) of the at least one sample of dried physiological fluid.

Certain embodiments may provide, for example, a method for detecting a neurological condition (for example a neural injury or a degenerative neurological disease) using dried capillary blood. In certain embodiments, for example, the method may comprise: providing a liquid sample derived from dried capillary blood (for example a liquid sample comprising an elution product of the dried capillary blood or a supernatant fluid obtained from the dried capillary blood). In certain embodiments, for example, the method may comprise: diluting the liquid sample to adjust the liquid sample to within a working range (for example a range of quantifiable signals or a range of detectable and countable signals) in a digital immunoassay, the working range comprising: a) at least one biomarker at a concentration in the diluted liquid sample that is greater than a corresponding at least one limit of quantification of the digital immunoassay; and b) at least one threshold indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) that is greater than the at least one corresponding limit of quantification. In certain embodiments, for example, the method may comprise: quantifying the at least one biomarker concentration via the digital immunoassay.

A. In certain embodiments, for example, the method may further comprise: obtaining a dilution factor for the diluting, comprising (a) quantifying a component concentration in a further portion of the liquid sample, and (b) comparing the component concentration with a predetermined value. In certain embodiments, for example, the component concentration may be insensitive to the functioning of the CNS.

Certain embodiments may provide, for example, a method for detecting a neurological condition (for example a neural injury or a degenerative neurological disease) using dried capillary blood. In certain embodiments, for example, the method may comprise: providing a liquid sample derived from dried capillary blood. In certain embodiments, for example, the method may comprise: diluting a portion of the liquid sample to align at least one biomarker concentration in the diluted portion of the liquid sample with a classification model for determining a risk of the neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the method may comprise: quantifying the at least one biomarker concentration via a digital immunoassay.

Certain embodiments may provide, for example, a dual-assay method to detect a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the dual-assay method may comprise: quantifying NF-L (or another biomarker, for example GFAP or Tau) in a first fluid sample, the first fluid sample derived from dried capillary blood of a neonate. In certain embodiments, for example, the dual-assay method may comprise: determining that the quantified NF-L exceeds a predetermined threshold. In certain embodiments, for example, the dual-assay method may comprise: performing, in response to the determining, at least one digital immunoassay on a second fluid sample derived from the neonate to quantify at least one biomarker for the neurological condition (for example a neural injury or a degenerative neurological disease), the at least one biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Certain embodiments may provide, for example, a method to screen for a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the method may comprise: providing a first fluid sample derived from dried capillary blood, the dried capillary blood obtained from a subject (i.e., liquid capillary blood obtained from a subject and then dried) following a medical procedure on the subject. In certain embodiments, for example, the method may comprise: quantifying a first component (for example a non-CNS marker, a stable reference compound, total Sodium, or a first biomarker indicative of the presence or absence of the neurological condition (for example a neural injury or a degenerative neurological disease)) present in the first fluid sample. In certain embodiments, for example, the method may comprise: computing a dilution factor based on the quantified first component. In certain embodiments, for example, the method may comprise: diluting a second fluid sample by the dilution factor with a diluent (for example one of the diluents disclosed herein or in one of the INCORPORATED REFERENCES), the second fluid sample derived from the dried capillary blood In certain embodiments, for example, the method may comprise: quantifying (for example determining a concentration of) at least one biomarker in the diluted second fluid sample via at least one digital immunoassay (for example at least one multiplexed digital immunoassay), the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE (or the at least one biomarker selected from the group consisting of GFAP, Tau, A beta 40, A beta 42, S100B, and NSE, exclusive of NF-L and/or UCH L1).

Certain embodiments may provide, for example, a method to screen for a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the method may comprise: providing a first series of fluid samples derived from a series of dried capillary blood samples, the series of dried capillary blood samples obtained from a subject at predetermined (or scheduled) time intervals following a medical procedure on the subject. In certain embodiments, for example, the method may comprise: quantifying concentrations of a first component (for example a baseline biomarker concentration) present in the first series of fluid samples. In certain embodiments, for example, the method may comprise: computing a series of dilution factors based on the quantified concentrations. In certain embodiments, for example, the method may comprise: diluting a second series of fluid samples based on the series of dilution factors, the second series of fluid samples derived from the series of dried capillary blood samples. In certain embodiments, for example, the method may comprise: quantifying concentrations of at least one biomarker in the diluted second series of fluid samples via a series of digital immunoassay, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Any of the methods, tests, protocol, assays, kits, or systems disclosed herein may comprise preparing one or more calibration curves to convert an assay result (for example signal readings or average exposed bead measurements) for one or more biomarkers into a measure of concentration of the one or more biomarkers (for example a concentration expressed as pg/mL or pmole/L). In certain embodiments, for example, the one or more calibration curves may comprise a plurality (for example a series) of calibration curves for a multiplex assay (for example a multiplex assay configured to quantify concentrations of a panel of biomarkers, such as a panel of biomarkers indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) in a subject when present in a dried blood sample obtained from the subject). In certain embodiments, for example, a series of multi-constituent calibrators having known concentrations of multiple biomarkers may be prepared in a diluent and assayed, and the resulting assay results correlated (for example by linear or nonlinear regression) to the known concentrations to obtain a calibration curve for each biomarker of the multiple biomarkers.

In certain embodiments, for example, the multi-constituent calibrators may comprise known concentrations of one or more of the following biomarkers: NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the multi-constituent calibrators may comprise known concentrations of NF-L, GFAP, UCH L1, and Tau. In certain embodiments, for example, the multi-constituent calibrators may comprise known concentrations of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the multi-constituent calibrators may comprise known concentrations of NF-L, GFAP, and Tau. In certain embodiments, for example, the multi-constituent calibrators may comprise known concentrations of NF-L, GFAP, Tau, A beta 40, A beta 42, S100B, and NSE.

In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on experimental design principles. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising an orthogonal experimental design. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising a principal components analysis. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising a randomized experimental design. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising a factorial experimental design. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising a response surface methodology. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on an experimental design comprising an optimal experimental design. In certain embodiments, for example, the biomarker concentrations in the series of multi-constituent calibrators may be selected based on known cross-reactivities between one or more of the biomarkers and one or more capture agents for the one or more biomarkers.

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions A-H (concentrations expressed as pg/mL):

A A beta beta Composition NF-L GFAP UCH Ll Tau 40 42 S100B NSE A 0 0 0 0 0 0 0 0 B 0.25-0.75 0.5-1.5  5-15 0.05-0.15 C 1.25-1.75 2-5 20-40 0.2-0.4 D 4-6  6-15  75-125 0.5-1.5 E 10-20 20-40 250-350 2-5 F 25-75  75-125  800-1200  8-12 G 100-200 250-350 2000-4000 20-40 H 400-500  800-1100  8000-10000  70-100

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions I-P (concentrations expressed as pg/mL):

A A beta beta Composition NF-L GFAP UCH Ll Tau 40 42 S100B NSE I 0 0 0 0 0 0 0 0 J 0.25-0.75 0.5-1.5  5-15 0.05-0.15 0-250 0-250 0-250 0-250 K 1.25-1.75 2-5 20-40 0.2-0.4 0-250 0-250 0-250 0-250 L 4-6  6-15  75-125 0.5-1.5 0-250 0-250 0-250 0-250 M 10-20 20-40 250-350 2-5 0-250 0-250 0-250 0-250 N 25-75  75-125  800-1200  8-12 0-250 0-250 0-250 0-250 O 100-200 250-350 2000-4000 20-40 0-250 0-250 0-250 0-250 P 400-500  800-1100  8000-10000  70-100 0-250 0-250 0-250 0-250

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions Q-X (concentrations expressed as pg/mL):

A A UCH beta beta Composition NF-L GFAP L1 Tau 40 42 S100B NSE Q 0 0 0 0 0 0 0 0 R 0.25-0.75 0.5-1.5 0 0.05-0.15 0-250 0-250 0-250 0-250 S 1.25-1.75 2-5 0 0.2-0.4 0-250 0-250 0-250 0-250 T 4-6  6-15 0 0.5-1.5 0-250 0-250 0-250 0-250 U 10-20 20-40 0 2-5 0-250 0-250 0-250 0-250 V 25-75  75-125 0  8-12 0-250 0-250 0-250 0-250 W 100-200 250-350 0 20-40 0-250 0-250 0-250 0-250 X 400-500  800-1100 0  70-100 0-250 0-250 0-250 0-250

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions Y-AF (concentrations expressed as pg/mL):

UCH A beta A beta Composition NF-L GFAP L1 Tau 40 42 S100B NSE Y 0 0 0 0 0 0 0 0 Z 0 0.5-1.5 0 0.05-0.15 0-250 0-250 0-250 0-250 AA 0 2-5 0 0.2-0.4 0-250 0-250 0-250 0-250 AB 0  6-15 0 0.5-1.5 0-250 0-250 0-250 0-250 AC 0 20-40 0 2-5 0-250 0-250 0-250 0-250 AD 0  75-125 0  8-12 0-250 0-250 0-250 0-250 AE 0 250-350 0 20-40 0-250 0-250 0-250 0-250 AF 0  800-1100 0  70-100 0-250 0-250 0-250 0-250

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions AG-AN (concentrations expressed as pg/mL):

A A UCH beta beta Composition NF-L GFAP L1 Tau 40 42 S100B NSE AG 0 0 0 0 0 0 0 0 AH 0.5 1 10 0.1 AI 1.5 3 30 0.3 AJ 5 10 100 1 AK 15 30 300 3 AL 50 100 1000 10 AM 150 300 3000 30 AN 450 900 9000 90

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions AO-AV (concentrations expressed as pg/mL):

Compo- UCH A beta A beta sition NF-L GFAP L1 Tau 40 42 S100B NSE AO 0 0 0 0 0 0 0 0 AP 0.5 1 10 0.1 0-250 0-250 0-250 0-250 AQ 1.5 3 30 0.3 0-250 0-250 0-250 0-250 AR 5 10 100 1 0-250 0-250 0-250 0-250 AS 15 30 300 3 0-250 0-250 0-250 0-250 AT 50 100 1000 10 0-250 0-250 0-250 0-250 AU 150 300 3000 30 0-250 0-250 0-250 0-250 AV 450 900 9000 90 0-250 0-250 0-250 0-250

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions AW-BD:

A A UCH beta beta Composition NF-L GFAP L1 Tau 40 42 S100B NSE AW 0 0 0 0 0 0 0 0 AX 0.5 1 0 0.1 0-250 0-250 0-250 0-250 AY 1.5 3 0 0.3 0-250 0-250 0-250 0-250 AZ 5 10 0 1 0-250 0-250 0-250 0-250 BA 15 30 0 3 0-250 0-250 0-250 0-250 BB 50 100 0 10 0-250 0-250 0-250 0-250 BC 150 300 0 30 0-250 0-250 0-250 0-250 BD 450 900 0 90 0-250 0-250 0-250 0-250

In certain embodiments, for example, the series of multi-constituent calibrators may comprise one or more (for example all) of compositions BE-BL (concentrations expressed as pg/mL):

A A UCH beta beta Composition NF-L GFAP L1 Tau 40 42 S100B NSE BE 0 0 0 0 0 0 0 0 BF 0 1 0 0.1 0-250 0-250 0-250 0-250 BG 0 3 0 0.3 0-250 0-250 0-250 0-250 BH 0 10 0 1 0-250 0-250 0-250 0-250 BI 0 30 0 3 0-250 0-250 0-250 0-250 BJ 0 100 0 10 0-250 0-250 0-250 0-250 BK 0 300 0 30 0-250 0-250 0-250 0-250 BL 0 900 0 90 0-250 0-250 0-250 0-250

In certain embodiments, for example, at least one (for example all) of the multi-constituent calibrators may comprise one or more buffers (or a buffering system) (for example phosphate buffer), one or more ions (for example Na⁺ and K⁺), one or more ionic salts (for example NaCl and KCl), one or more blocking agents, one or more surfactants, one or more complexing agents (for example ethylenediaminetetraacetic acid (EDTA) or a salt thereof), one or more anti-microbial agents (for example a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone), or a combination of two or more of the foregoing.

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more buffers, or a buffering system (for example one or more of the buffers or buffering systems disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more buffers may be selected from the group consisting of citrate buffers, phosphate buffers, borate buffers, tris(hydroxymethyl)aminomethane (Tris) buffers, barbital buffers, bicarbonates, as well as Good buffers (non-toxic to cells; not absorbed through cell membranes and feature pKa values at or near physiological pH) such as but not limited to N,N′-bis(2-hydroxyethyl)glycine (BIC IN), 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1,3-propanediol (BISTRIS), 2-(cyclohexylamino)ethane-2-sulfonic acid (CHES), N-2-(hydroxyethyl)piperazine-N′-2-ethanesulfonic acid (HEPES), N-(2-hydroxyethyl)piperazine-N′-3-propanesulfonic acid (HEPPS), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), piperazine-N, N′-bis(2-ethanesulfonic acid) (PIPES), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), and N-tris(hydroxymethyl)methylglycine (TRICINE), or a combination of two or more of the foregoing. In certain embodiments, for example, the multi-constituent calibrators may comprise a buffering system comprising a combination of buffers. In certain embodiments, for example, the multi-constituent calibrators may contain a phosphate buffer (for example phosphate at a concentration of between 10 mM and 100 mM, such as phosphate at a concentration of between 30 mM and 70 mM, or at a concentration of 50 mM, or sodium phosphate (dibasic) at a concentration of between 0.1% and 20%, such as sodium phosphate (dibasic) at a concentration of between 0.5% and 15%, or at a concentration of between 1% and 10%, and/or potassium phosphate (monobasic) at a concentration of between 0.01% and 10%, such as potassium phosphate (monobasic) at a concentration of between 0.5% and 5% or at a concentration of between 0.1% and 1%).

In certain embodiments, for example, the one or more ions may comprise one or more ions (for example one or more of the ions disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ions may be selected from the group consisting of Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Cu²⁺, Mn²⁺, Fe²⁺, Fe³⁺, NH₄ ⁺, Cl⁻, Br⁻, carbonate, hydrogen carbonate, hydrogen sulfate, hydrogen sulfite, sulfate, sulfite, monohydrogen phosphate, dihydrogen phosphate, nitrate, nitrite, permanganate, silicate, sulphates, pyrosulphates, pyrophosphates, citrates, cacodylates, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more ions may comprise Cl⁻ (for example Cl⁻ at a concentration of between 100 mM and 200 mM, such as Cl⁻ at a concentration of between 120 mM and 160 mM, or at a concentration of 141.7 mM). In certain embodiments, for example, the one or more ions may comprise Na⁺ (for example Na⁺ at a concentration of between 100 mM and 200 mM, such as Na⁺ at a concentration of between 120 mM and 160 mM, or at a concentration of 137 mM). In certain embodiments, for example, the one or more ions may comprise K⁺ (for example K⁺ at a concentration of between 1 mM and 5 mM, such as K⁺ at a concentration of between 2 mM and 3 mM, or at a concentration of 2.7 mM). In certain embodiments, for example, the one or more ions may comprise Mg²⁺ (for example Mg²⁺ at a concentration of between 0.1 mM and 5 mM, such as Mg²⁺ at a concentration of between 0.5 mM and 2.5 mM, or at a concentration of 1 mM). In certain embodiments, for example, the one or more ions may comprise phosphate (for example phosphate at a concentration of between 10 mM and 100 mM, such as phosphate at a concentration of between 30 mM and 70 mM, or at a concentration of 50 mM).

In certain embodiments, for example, the ions may form one or more ionic salts (for example one or more of the ionic salts disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ionic salts may be selected from the group consisting of KCl, NaCl, MgCl₂, KH₂PO₄, K₂HPO₄, NaH₂PO₄, Na₂HPO₄, NaHCO₃ and other suitable ionic salts. In certain embodiments, for example, the one or more ionic salts may comprise KCl (for example KCl at a concentration of between 1 mM and 5 mM, such as KCl at a concentration of between 2 mM and 3 mM, or at a concentration of 2.7 mM or KCl at a concentration of between 0.001% and 1%, such as KCl at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%). In certain embodiments, for example, the one or more ionic salts may comprise NaCl (for example NaCl at a concentration of between 100 mM and 200 mM, such as NaCl at a concentration of between 120 mM and 160 mM, or at a concentration of 137 mM, or NaCl at a concentration of between 0.05% and 20%, such as NaCl at a concentration of between 0.1% and 10%, or at a concentration of 0.5% and 5%). In certain embodiments, for example, the one or more ionic salts may comprise MgCl₂ (for example MgCl₂ at a concentration of between 0.1 mM and 5 mM, such as MgCl₂ at a concentration of between 0.5 mM and 2.5 mM, or at a concentration of 1 mM).

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more surfactants (for example one or more of the surfactants disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more surfactants may comprise one or more ionic surfactants. In certain embodiments, for example, the one or more surfactants may comprise one or more nonionic surfactants. In certain embodiments, for example, the one or more surfactants may comprise a glycidyl surfactant (for example 10G surfactant (for example 10G surfactant at a concentration of between 0.01% and 1%, or at a concentration of 0.1%)). In certain embodiments, for example, the one or more surfactants may comprise one or more detergents (for example one or more of the detergents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more detergents may be selected from the group consisting of nonionic, cationic, anionic and amphoteric forms. In certain embodiments, for example, the one or more detergents may be selected from the group consisting of polyoxyethylene sorbitan alcohol detergents (i.e., the Tween series), polyoxyethylene alcohols such as the non-ionic, non-denaturing detergent sold under the trademark Nonidet™ P-40 or polyoxyethylene ethers such as Triton™ X-100, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more detergents may comprise Triton™ X-100 (for example Triton™ X-100 at a concentration of between 0.005% and 2% (for example at a concentration of 0.5%), between 0.1% and 1%, or the multi-constituent calibrators may comprise Triton™ X-100 at a concentration of between 0.25% and 0.75%). In certain embodiments, for example, the surfactant may be at a concentration of between 0.005% and 2%, between 0.01% and 1.5%, or at a concentration of between 0.1% and 1%.

In certain embodiments, multi-constituent calibrators may comprise one or more immunoglobulins (or antibodies or fragments thereof) (for example one of the immunoglobulins (or antibodies or fragments thereof) thereof disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more immunoglobulins may be selected from the classes consisting of IgA, IgD, IgE, IgG, IgM, a sub-class of one or more of the foregoing, or a combination of two of more of the foregoing. In other embodiments, for example, the one or more immunoglobulins may not belong to any particular class. In certain embodiments, for example, the one or more immunoglobulins may contain different heavy-chain constant domains that correspond to the different classes of immunoglobulins, such as alpha, delta, epsilon, gamma, and mu, respectively. In other embodiments, for example, the one or more immunoglobulins may contain heavy-chain constant domains that do not correspond to any particular class of immunoglobulins. In certain embodiments, for example, the one or more immunoglobulins may comprise but may be not limited to an immunoglobulin of any subclasses (isotypes) in the major classes, such as IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2. In certain embodiments, for example, the one or more immunoglobulins may be not of any subclasses (isotypes) in the major classes. In certain embodiments, for example, the one or more immunoglobulins may be of murine, rat, human, bovine, goat, rabbit, or sheep origin. In certain embodiments, for example, the one or more immunoglobulins may comprise a natural immunoglobulin. In certain embodiments, for example, the one or more immunoglobulins may comprise a genetically modified immunoglobulin. In certain embodiments, for example, the genetically modified immunoglobulin may be a chimeric or humanized immunoglobulin. In certain embodiments, for example, the one or more immunoglobulins may be selected from the group consisting of human IgA, human IgD, human IgE, human IgG, human IgM, murine IgA, murine IgD, murine IgE, murine IgG, murine IgM, rat IgA, rat IgD, rat IgE, rat IgG, rat IgM, bovine IgA, bovine IgD, bovine IgE, bovine IgG, bovine IgM, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more immunoglobulins may comprise human IgG (for example human IgG at a concentration of between 1 mg/mL and 10 mg/mL, of between 3 mg/mL and 7 mg/mL, or at a concentration of 5 mg/mL).

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more blocking agents (for example one or more of the blocking agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more blocking agents may be configured to prevent non-specific binding to one or more assay surfaces, such as a microtiter well surface. In certain embodiments, for example, the one or more blocking agents may be configured to prevent non-specific binding to one or more target analytes (for example NF-L, GFAP, etc.). In certain embodiments, for example, the one or more blocking agents may be configured to prevent non-specific binding to a capture agent or a detection agent (for example the capture agent or detection agent described herein). In certain embodiments, for example, the one or more blocking agents may be selected from the group consisting of detergents (for example Triton™ X-100 and a Tween), BSA, ovalbumin, glucose, other sugars, polyethylene glycol, dextran, lysozyme, and poly L-lysine, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more blocking agents may comprise BSA (for example BSA at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%).

In certain embodiments, for example, one of the one or more immunoglobulins (or antibodies) may be a heterophilic interference inhibitor. In certain embodiments, for example, human IgG may be a heterophilic interference inhibitor. In certain embodiments, for example, one of the one or more immunoglobulins (or antibodies) may be a heterophilic interference molecule. In certain embodiments, for example, human IgG may be a heterophilic interference molecule. In certain embodiments, for example, the multi-constituent calibrators may comprise one or more interference molecules (for example one or more of the interference molecules disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more interference molecules may be selected from the group consisting of HAGA, HAMA, HARA, HASA, rheumatoid factor, or a combination of two or more of the foregoing.

In certain embodiments, for example, the one or more blocking agents may comprise a component that is a heterophilic interference inhibitor when added to a predetermined type of sample (for example a blood sample, urine sample, CSF sample, etc.). In certain embodiments, for example, the heterophilic interference inhibitor may block one or more heterophilic interference molecules from binding to one or more of the analytes disclosed herein, such as NF-L, GFAP, UCH L1 and/or Tau. In certain embodiments, for example, the heterophilic interference inhibitor may block one or more heterophilic interference molecules from binding a capture agent or a detection agent (for example the capture agents or detection agents described herein). In certain embodiments, for example, at least one of the one or more inhibitors may be selected from the group consisting of BSA, protein L, collagen, PEG4000/6000, whole normal animal serum (for example mouse serum, rat serum, goat serum, rabbit serum, sheep serum), an animal based IgG aggregate (for example mouse IgG, rat IgG, rabbit IgG, goat IgG, sheep IgG), and an antibody derived from goat, mouse, rabbit or sheep that recognizes a HAGA, HAMA, HARA, HASA, rheumatoid factor, Superchemiblock™ heterophile blocking agent (Millipore, Billerica, Mass.), TRU Block™ (Meridian Bioscience, Memphis, Tenn.), immunoglobulin-inhibiting reagent (IIR; Bioreclamation, Inc., Westbury, N.Y.), heterophile blocking tubes (Scantibodies Laboratory, Santee, Calif.), StabliGuard immunoassay stabilizer (SurModics, Inc., Eden Prairie, Minn.), one of the blocking agents disclosed in the INCORPORATED REFERENCES, or a combination of two or more of the foregoing. In certain embodiments, for example, the blocking agent may be an interference blocker at a concentration of between 0.001% and 1%, between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%.

In certain embodiments, for example, the heterophilic interference inhibitor may comprise an antibody (for example IgG, IgG, IgM, IgE or IgD), for example of animal (for example mouse, rabbit, sheep, goat, donkey, and other suitable animals) origin. In certain embodiments, for example, the antibody may specifically bind and neutralize one or more heterophilic antibodies, one or more rheumatoid factors, or one or more other interference molecules. For example, the attachment of the immunoglobulin to a heterophilic antibody prevents the heterophilic antibody from binding (capturing) an antibody that may be specific for an analyte or a detection antibody. The one or more heterophilic interference inhibitors may be one or more antibodies that may not bind to one or more analytes or one or more affinity antibodies that may be specific for (for example may specifically bind to) the one or more analytes.

In certain embodiments, for example, the one or more binding agents may comprise one or more heterophile antibody blocking agents (for example one or more of the heterophile antibody blocking agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more binding agents may comprise Superchemiblock™ (for example Superchemiblock™ at a concentration of between 10 μg/mL and 100 μg/mL, such as Superchemiblock™ at a concentration of between 30 μg/mL and 70 μg/mL, at a concentration of 50 μg/mL, between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.05%).

In certain embodiments, for example, the one or more binding agents may comprise one or more human anti-mouse antibody (HAMA) blockers (for example one of the HAMA blockers disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more HAMA blockers may comprise TRU Block™ (for example TRU Block™ at a concentration of between 1 mcg/mL and 100 mcg/mL, such as TRU Block™ at a concentration of between 5 mcg/mL and 15 mcg/mL, or at a concentration of 10 mcg/mL).

In certain embodiments, for example, the one or more binding agents may bind to one or more interference molecules. In certain embodiments, for example, more than one type of binding agent may bind to the same interference molecule. In certain embodiments, for example, the one or more blocking agents may comprise a first binding agent and a second binding agent. In certain embodiments, for example, the first binding agent and the second binding agent may bind to the same interference molecule. In certain embodiments, for example, the first binding agent and the second binding agent may not bind to the same interference molecule. In certain embodiments, for example, the one or more blocking agents may comprise a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of different types of binding agents. In some embodiments, the one or more binding agents may bind to a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of different types of interference molecules.

In certain embodiments, for example, the more than one binding agents may be utilized in a one-to-one ratio. For instance, the first binding agent and the second binding agent may present at equal or approximately equal concentrations (for example molar concentrations). In certain embodiments, for example, the more than one binding agents may be present at different concentrations (for example molar concentrations). In certain embodiments, for example, the first binding agent may be present at a concentration that is at least 1 times greater than the concentration of the second binding agent, for example at least 2 times, at least 3 times, at least 4 times, at least 5 times, or the first binding agent may be present at a concentration that is at least 6 times greater than the concentration of the second binding agent. In certain embodiments, for example, the one or more binding agents may be a plurality of binding agents comprising TRU Block™ and Superchemiblock™ (for example TRU Block™ and Superchemiblock™ at a ratio of between 1:1 and 1:10, such as TRU Block™ and Superchemiblock™ at a ratio of between 1:3 and 1:7, or at a ratio of 1:5).

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more sugars (for example one or more of the sugars disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more sugars may comprise dextrose (for example dextrose at a concentration of between 0.005% and 0.05% (for example at a concentration of 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.06%).

In certain embodiments, for example, the multi-constituent calibrators may comprise BgG (for example BgG at a concentration of between 0.005% and 0.05% (for example at a concentration of 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.01%).

In certain embodiments, for example, the multi-constituent calibrators may comprise urea (for example urea at a concentration of between 0.5 mM and 100 mM (for example at a concentration of 10 mM), between 1 mM and 20 mM, between 1 mM and 10 mM, or at a concentration of between 3 mM and 7 mM, or urea at a concentration of between 0.001% and 1% (for example a concentration of 0.05%), between 0.005% and 0.5%, or at a concentration of 0.01%).

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more complexing agents that are capable of forming a complex with a metal ion (for example one of the complexing agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more complexing agents may be selected from the group consisting of EDTA, deferoxamine (DESFERAL), NTA, β-alaninediacetic acid (βADA), diethylenetriaminepentaacetic acid (DTPA), diethylenetriaminepentakis-methylenephosphonic acid (DTPMP), nitrilotriacetic acid (NTA), N-bis[2-1,2-dicarboxyethoxy)ethyl]glycine (BCA5), N-bis[2-1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), gluconic acid and tetracis(2-hydroxypropyl)ethylenediamine (THPED), other suitable complexing agents, or a combination of two or more of the foregoing. In certain embodiments, for example, the complexing agent may comprise EDTA or a salt of EDTA (for example EDTA or salt of EDTA at a concentration of between 1 mM and 50 mM, of between 1 mM and 10 mM, or at a concentration of 5 mM, or EDTA or salt of EDTA at a concentration of 0.02-10%, 0.1-5%, or at a concentration of 0.2-2%). In certain embodiments, for example, the salt of EDTA may be sodium edetate or EDTA disodium salt dihydrate.

In certain embodiments, for example, the multi-constituent calibrators may comprise one or more anti-microbial agent (for example one of the anti-microbial agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more anti-microbial agents may be selected from the group consisting of benzalkonium chloride, sodium azide, sodium fluoride, phenoxyethanol, sodium dehydroacetate, chlorobutanol, phenylethanol, 4-chloroxylenol, 1-hydroxypyridine-2-thione, paraben derivatives, glutaraldehyde, formaldehyde, nalidixic acid, sodium-2-pyridinethiol-1-oxide (sold under the trademark Sodium Omadine™), the bactericidal antimicrobial sold under the trademark Triadine™ 3, the bactericidal antimicrobial sold under the trademark Triadine™ 10, combinations of 5-chloro-2-methyl-4-isothiazolin-2-one, 2-methyl-4-isothiazolin-3-one, 5-bromo-5-nitro-1,3-dioxane, derivatives of each of these compounds, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more anti-microbial agents may be commercially available and selected from the group consisting of reagents comprising aqueous combinations of 5-chloro-2-methyl-4-methyl-4-isothiazolin-2-one and 2-methyl-4-isothiazolin-3-one (Supelco, under the trademark Proclin), for example, the preservative sold under the trademark ProClin™ 150 reagent (Supelco, an aqueous mixture of 1.15% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.35% of 2-methyl-4-isothiazolin-3-one), the preservative sold under the trademark ProClin™ 300 reagent (Supelco, a mixture of 2.3% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.7% of 2-methyl-4-isothiazolin-3-one in a solvent consisting of a modified glycol and alkyl carboxylate), the preservative sold under the trademark Proclin™ 5000 reagent (Supelco, 2-methyl-4-isothiazolin-3-one in a dipropylene glycol solvent), the preservative sold under the trademark Bronidox® L reagent (Cognis Corporation, biocide 5-bromo-5-nitro-1,3-dioxane), or a combination of two or more of the foregoing. In certain embodiments, for example, the multi-constituent calibrators may comprise a combination of two or more anti-microbial agents in any ratio effective to combat microbial growth. In certain embodiments, for example, the one or more anti-microbial agents may comprise benzalkonium chloride. In certain embodiments, for example, the one or more anti-microbial agents may comprise ProClin™ 300 (for example ProClin™ 300 at a concentration of between 0.005% and 0.05% (for example at a concentration of 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%). In certain embodiments, for example, the one or more anti-microbial agents may comprise a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (for example the mixture having a total concentration of between 0.01% and 5%, between 0.05% and 1%, or having a total concentration of between 0.1% and 0.5%).

In certain embodiments, for example, the multi-constituent calibrators may have a pH of between 2.5 and 10 (for example a pH of between 5 and 9, of between 7 and 8, a pH of 7.4, or an approximately neutral pH).

In certain embodiments, for example, the multi-constituent calibrators may comprise phosphate buffered saline, KCl, BSA, 10G Surfactant, TRU Block™, EDTA, and an anti-microbial agent. In certain embodiments, for example, the multi-constituent calibrators may comprise: phosphate buffered saline, KCl at a concentration of between 3 mM and 5 mM, BSA at a concentration of between 1% and 3%, 10G surfactant at a concentration of between 0.05% and 0.15%, TRU Block™ at a concentration of between 5 mcg/mL and 15 mcg/mL, EDTA or salt of EDTA at a concentration of between 3 mM and 7 mM, and an anti-microbial agent, wherein the multi-constituent calibrators may have a pH of between 7 and 8. In certain embodiments, for example, the multi-constituent calibrators may comprise: phosphate buffered saline, KCl at a concentration of 2.7 mM, BSA at a concentration of 2%, 10G surfactant at a concentration of 0.1%, TRU Block™ at a concentration of 10 mcg/mL, EDTA or salt of EDTA at a concentration of 5 mM, and an anti-microbial agent, wherein the multi-constituent calibrators may have a pH of 7.4. In certain embodiments, for example, the multi-constituent calibrators may comprise: phosphate buffered saline, dextrose at a concentration of 0.06%, BSA at a concentration of 0.02%, BgG at a concentration of 0.01%, urea at a concentration of 5 mM, Triton™ X-100 at a concentration of 0.5%, TRU Block™ at a concentration of 10 mcg/mL, Superchemiblock™ at a concentration of 0.05%, and an anti-microbial agent, wherein the multi-constituent calibrators may have a pH of 7.4.

In certain embodiments, for example, the multi-constituent calibrators may comprise water, sodium phosphate (dibasic), potassium phosphate (monobasic), NaCl, KCl, BSA, a surfactant (for example 10G Surfactant), an interference blocker (for example TRU Block™), EDTA disodium salt dihydrate, and an anti-microbial agent (or a mixture of anti-microbial agents). In certain embodiments, for example, the multi-constituent calibrators may comprise: water at a concentration between 90% and 100%, sodium phosphate (dibasic) at a concentration between 1% to 10%, potassium phosphate (monobasic) at a concentration between 0.1% and 1%, NaCl at a concentration between 0.5% and 5%, KCl at a concentration of between 0.01% and 0.1%, BSA at a concentration of between 0.01% and 0.1%, a surfactant at a concentration of between 0.1% and 1%, an interference blocker at a concentration of between 0.01% and 0.1%, EDTA or salt of EDTA at a concentration of between 0.2% and 2%, and an anti-microbial agent at a concentration between 0.1% and 0.5%, wherein the multi-constituent calibrators may have a pH of between 7 and 8.

In certain embodiments, for example, the multi-constituent calibrators may comprise: phosphate, one or more salts (for example NaCl and/or KCl), BSA, 10G Surfactant, and EDTA. In certain embodiments, for example, the multi-constituent calibrators may comprise: 20-200 mM phosphate, 50-250 mM NaCl, 1-5 mM KCl, 0.5-5% BSA, 0.05-0.25% 10G Surfactant, 1-10 mcg/mL TRU block, 0.005-0.25% ProClin™ 300, and 0.5-20 mM EDTA, wherein the multi-constituent calibrators may have a pH of 6-8.5. In certain embodiments, for example, the multi-constituent calibrators may comprise human IgG (for example human IgG at a concentration of 0.5-20 mg/mL (for example a concentration of 5 mg/mL). In certain embodiments, for example, the multi-constituent calibrators may comprise: 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block™, 0.05% ProClin™ 300, and 5 mM EDTA, wherein the multi-constituent calibrators may have a pH of 7.4.

Any of the methods, tests, assays, kits, or systems disclosed herein may comprise a sample diluent configured to dilute the liquid sample (for example a liquid sample derived from a dried capillary blood sample) into a working range (for example a working range of analyte concentrations or working range of fluid properties of such as viscosity of the diluted liquid sample) for performing an immunoassay. In certain embodiments, for example, the sample diluent may be mixed with the liquid sample to make a diluted liquid sample (for example a 2× dilution, 4× dilution, 8× dilution, 16× dilution, 32× dilution, 64× dilution, or 128× dilution) suitable for analysis. In certain embodiments, for example, the diluent may be an aqueous diluent.

In certain embodiments, for example, the diluent may comprise a plurality of components selected from the group consisting of one or more buffers (or a buffering system), one or more ions, one or more ionic salts, one or more blocking agents, one or more surfactants, one or more complexing agents, and one or more anti-microbial agents. The diluent may contain any of the buffers (or buffer systems), ions, ionic salts, blocking agents, surfactants, complexing agents, immunoglobulins, and/or anti-microbial agents disclosed herein (for example disclosed in the discussion of the multi-component calibrators) or in one of the INCORPORATED REFERENCES.

In certain embodiments, for example, the diluent may comprise one or more immunoglobulins (or antibodies or fragments thereof) (for example one of the immunoglobulins (or antibodies or fragments thereof) thereof disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more immunoglobulins may be selected from the classes consisting of IgA, IgD, IgE, IgG, IgM, a sub-class of one or more of the foregoing, or a combination of two of more of the foregoing. In other embodiments, for example, the one or more immunoglobulins may not belong to any particular class. In certain embodiments, for example, the one or more immunoglobulins may contain different heavy-chain constant domains that correspond to the different classes of immunoglobulins, such as alpha, delta, epsilon, gamma, and mu, respectively. In other embodiments, for example, the one or more immunoglobulins may contain heavy-chain constant domains that do not correspond to any particular class of immunoglobulins. In certain embodiments, for example, the one or more immunoglobulins may comprise but may be not limited to an immunoglobulin of any subclasses (isotypes) in the major classes, such as IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2. In certain embodiments, for example, the one or more immunoglobulins may be not of any subclasses (isotypes) in the major classes. In certain embodiments, for example, the one or more immunoglobulins may be of murine, rat, human, bovine, goat, rabbit, or sheep origin. In certain embodiments, for example, the one or more immunoglobulins may comprise a natural immunoglobulin. In certain embodiments, for example, the one or more immunoglobulins may comprise a genetically modified immunoglobulin. In certain embodiments, for example, the genetically modified immunoglobulin may be a chimeric or humanized immunoglobulin. In certain embodiments, for example, the one or more immunoglobulins may be selected from the group consisting of human IgA, human IgD, human IgE, human IgG, human IgM, murine IgA, murine IgD, murine IgE, murine IgG, murine IgM, rat IgA, rat IgD, rat IgE, rat IgG, rat IgM, bovine IgA, bovine IgD, bovine IgE, bovine IgG, bovine IgM, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more immunoglobulins may comprise human IgG (for example human IgG at a concentration of between 1 mg/mL and 10 mg/mL, of between 3 mg/mL and 7 mg/mL, or at a concentration of 5 mg/mL).

In certain embodiments, for example, the diluent may comprise phosphate buffered saline, KCl, BSA, 10G Surfactant, TRU Block™, EDTA, and an anti-microbial agent. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, KCl at a concentration of between 3 mM and 5 mM, BSA at a concentration of between 1% and 3%, 10G surfactant at a concentration of between 0.05% and 0.15%, TRU Block™ at a concentration of between 5 mcg/mL and 15 mcg/mL, EDTA or salt of EDTA at a concentration of between 3 mM and 7 mM, and an anti-microbial agent, wherein the diluent may have a pH of between 7 and 8. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, KCl at a concentration of 2.7 mM, BSA at a concentration of 2%, 10G surfactant at a concentration of 0.1%, TRU Block™ at a concentration of 10 mcg/mL, EDTA or salt of EDTA at a concentration of 5 mM, and an anti-microbial agent, wherein the diluent may have a pH of 7.4. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, dextrose at a concentration of 0.06%, BSA at a concentration of 0.02%, BgG at a concentration of 0.01%, urea at a concentration of 5 mM, Triton™ X-100 at a concentration of 0.5%, TRU Block™ at a concentration of 10 mcg/mL, Superchemiblock™ at a concentration of 0.05%, and an anti-microbial agent, wherein the diluent may have a pH of 7.4.

In certain embodiments, for example, the sample diluent may comprise: phosphate, one or more ionic salts (for example NaCl, KCl, and/or MgCl₂), BSA, a sugar (for example dextrose), BgG, urea, Triton™ X-100, TRU block™, Superchemiblock™, and ProClin™ 300. In certain embodiments, for example, the sample diluent may comprise an IgG (for example a human IgG). In certain embodiments, for example, the sample diluent may comprise: 20-200 mM phosphate, 50-250 mM NaCl, 1-5 mM KCl, 0.005-0.1% BSA, 0.25-5 mM MgCl₂, 0.005-0.25% dextrose, 0.001-0.05% BgG, 0.5-10 mM urea, 0.05-2% Triton™ X-100, 1-100 mcg/mL TRU block™, 1-100 mcg/mL Superchemiblock™, 0.005-0.25% ProClin™ 300, and 0.5-20 mg/mL human IgG, wherein the sample diluent may have a pH of 6-8.5. In certain embodiments, for example, the sample diluent may comprise: 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton™ X-100, 10 mcg/mL TRU block™, 50 mcg/mL Superchemiblock™, and 0.05% ProClin™ 300, wherein the sample diluent may have a pH of 7.4. In certain embodiments, for example, the sample diluent may comprise: 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton™ X-100, 10 mcg/mL TRU block™, 50 mcg/mL Superchemiblock™, 0.05% ProClin™ 300, and 5 mg/mL human IgG, wherein the sample diluent may have a pH of 7.4.

In certain embodiments, for example, (a) the multi-constituent calibrators may comprise: phosphate, one or more salts (for example NaCl and/or KCl), BSA, 10G Surfactant, and EDTA; and (b) the sample diluent may comprise: phosphate, one or more ionic salts (for example NaCl, KCl, and/or MgCl₂), BSA, a sugar (for example dextrose), BgG, urea, Triton™ X-100, TRU block™, Superchemiblock™, ProClin™ 300, and optionally human IgG. In certain embodiments, for example, (a) the multi-constituent calibrators may comprise: 20-200 mM phosphate, 50-250 mM NaCl, 1-5 mM KCl, 0.5-5% BSA, 0.05-0.25% 10G Surfactant, 1-10 mcg/mL TRU block, 0.005-0.25% ProClin™ 300, and 0.5-20 mM EDTA, wherein the multi-constituent calibrators may have a pH of 6-8.5; and (b) the sample diluent may comprise: 20-200 mM phosphate, 50-250 mM NaCl, 1-5 mM KCl, 0.005-0.1% BSA, 0.25-5 mM MgCl₂, 0.005-0.25% dextrose, 0.001-0.05% BgG, 0.5-10 mM urea, 0.05-2% Triton™ X-100, 1-100 mcg/mL TRU block™, 1-100 mcg/mL Superchemiblock™, 0.005-0.25% ProClin™ 300, and optionally 0.5-20 mg/mL human IgG, wherein the sample diluent may have a pH of 6-8.5. In certain embodiments, for example, (a) the multi-constituent calibrators may comprise: 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block™, 0.05% ProClin™ 300, and 5 mM EDTA, wherein the multi-constituent calibrators may have a pH of 7.4; and (b) the sample diluent may comprise: 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton™ X-100, 10 mcg/mL TRU block™, 50 mcg/mL Superchemiblock™, 0.05% ProClin™ 300, and optionally 5 mg/mL human IgG, wherein the sample diluent may have a pH of 7.4.

Any of the methods, tests, assays, kits, or systems disclosed herein may comprise at least one detection reagent configured to selectively bind with an analyte (for example NF-L, GFAP, UCH L1, or Tau) and support detection of a detectable signal (for example through phosphorescence) in an immunoassay. In certain embodiments, for example, the at least one detection reagent may comprise a first detection reagent, a second detection reagent, and a third detection reagent.

In certain embodiments, for example, the first detection reagent may comprise one or more tagged antibodies (for example, an anti-human NF-L mouse IgG antibody, a Tau antibody coupled with biotin, an anti-human UCH L1 mouse IgG antibody and an anti-human GFAP mouse IgG antibody) that specifically binds to an analyte. In certain embodiments, for example, the first detection reagent may comprise an aqueous solution (for example a solution that may contain 90-100% water) containing the one or more tagged antibodies at a concentration of between 0.01% and 1%, between 0.05% and 0.5%, or at a concentration of between 0.01% and 0.1% (for example, an anti-human NF-L mouse IgG antibody, a Tau antibody coupled with biotin, an anti-human UCH L1 mouse IgG antibody and an anti-human GFAP mouse IgG antibody each at a concentration between 0.01% and 0.1%).

In certain embodiments, for example, the first detection reagent may comprise a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of components selected from the group consisting of one or more buffers (or a buffering system) (for example phosphate buffer), one or more ions (for example Na⁺, K⁺ and/or Cl⁻ ions), one or more ionic salts (for example NaCl and KCl), one or more complexing agents (for example EDTA disodium salt dehydrate), BSA, one or more blocking agents (for example interference blocker), and one or more anti-microbial agents (for example a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone).

In certain embodiments, for example, the first detection reagent may comprise one or more buffers, or a buffering system (for example one or more of the buffers or buffering systems disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more buffers may be selected from the group consisting of citrate buffers, phosphate buffers, borate buffers, tris(hydroxymethyl)aminomethane (Tris) buffers, barbital buffers, bicarbonates, as well as Good buffers (non-toxic to cells; not absorbed through cell membranes and feature pKa values at or near physiological pH) such as but not limited to N,N′-bis(2-hydroxyethyl)glycine (BIC IN), 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1,3-propanediol (BISTRIS), 2-(cyclohexylamino)ethane-2-sulfonic acid (CHES), N-2-(hydroxyethyl)piperazine-N′-2-ethanesulfonic acid (HEPES), N-(2-hydroxyethyl)piperazine-N′-3-propanesulfonic acid (HEPPS), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), piperazine-N, N′-bis(2-ethanesulfonic acid) (PIPES), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), and N-tris(hydroxymethyl)methylglycine (TRICINE), or a combination of two or more of the foregoing. In certain embodiments, for example, the first detection reagent may comprise a buffering system comprising a combination of buffers. In certain embodiments, for example, the RGP reagent may contain a phosphate buffer (for example phosphate at a concentration of between 10 mM and 100 mM, such as phosphate at a concentration in the range of between 30 mM and 70 mM, or 50 mM, or sodium phosphate (dibasic) at a concentration of between 0.1% and 30%, such as sodium phosphate (dibasic) at a concentration of between 0.5% and 20%, or at a concentration of between 1% and 10%, and potassium phosphate (monobasic) at a concentration of between 0.001% and 1%, such as potassium phosphate (monobasic) at a concentration of between 0.005% and 0.5% or at a concentration of between 0.01% and 0.1%).

In certain embodiments, for example, the first detection reagent may comprise one or more ions (for example one or more of the ions disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ions may be selected from the group consisting of Li⁺, Na⁺, K⁺, Mg2⁺, Ca2⁺, Cu2⁺, Mn2⁺, Fe2⁺, Fe3⁺, NH4⁺, Cl⁻, Br, carbonate, hydrogen carbonate, hydrogen sulfate, hydrogen sulfite, sulfate, sulfite, monohydrogen phosphate, dihydrogen phosphate, nitrate, nitrite, permanganate, silicate, sulphates, pyrosulphates, pyrophosphates, citrates, cacodylates and other suitable ions. In certain embodiments, for example, the one or more ions may comprise Cl⁻ (for example Cl⁻ at a concentration of between 100 mM and 200 mM, such as Cl⁻ at a concentration in the range of between 120 mM and 160 mM, or 141.7 mM). In certain embodiments, for example, the one or more ions may comprise Na⁺ (for example Na⁺ at a concentration of between 100 mM and 200 mM, such as Na⁺ at a concentration in the range of between 120 mM and 160 mM, or 137 mM). In certain embodiments, for example, the one or more ions may comprise K⁺ (for example K⁺ at a concentration of between 1 mM and 5 mM, such as K⁺ at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM).

In certain embodiments, for example, the ions may form one or more ionic salts (for example one or more of the ionic salts disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ionic salts may be selected from the group consisting of KCl, NaCl, MgCl₂, KH2PO4, K2HPO4, NaH2PO4, Na2HPO4, NaHCO3 and other suitable ionic salts. In certain embodiments, for example, the one or more ionic salts may comprise KCl (for example KCl at a concentration of between 1 mM and 5 mM, such as KCl at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM, or KCl at a concentration of 0.001-1%, such as KCl at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%). In certain embodiments, for example, the one or more ionic salts may comprise NaCl (for example NaCl at a concentration of between 100 mM and 200 mM, such as NaCl at a concentration in the range of between 120 mM and 160 mM, or 137 mM, or NaCl at a concentration of between 0.01% and 10%, such as NaCl at a concentration of between 0.05% and 5%, or at a concentration of 0.1% and 1%).

In certain embodiments, for example, the first detection reagent may comprise the nonionic surfactant polyol sold under the trademark Pluronic™ F-127 (for example Pluronic™ F-127 at a concentration of 0.001-1%, such as Pluronic™ F-127 at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%).

In certain embodiments, for example, the SBG reagent may comprise one or more complexing agents that are capable of forming a complex with a metal ion (for example one of the complexing agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more complexing agents may be selected from the group consisting of EDTA, deferoxamine (DESFERAL), NTA, β-alaninediacetic acid (β-ADA), diethylenetriaminepentaacetic acid (DTPA), diethylenetriaminepentakis-methylenephosphonic acid (DTPMP), nitrilotriacetic acid (NTA), N-bis[2-1,2-dicarboxyethoxy)ethyl]glycine (BCA5), N-bis[2-1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), gluconic acid and tetracis(2-hydroxypropyl)ethylenediamine (THPED), other suitable complexing agents, or a combination of two or more of the foregoing. In certain embodiments, for example, the complexing agent may comprise EDTA or a salt of EDTA (for example EDTA or salt of EDTA at a concentration of between 1 mM and 50 mM, of between 1 mM and 10 mM, or at a concentration of 5 mM, or EDTA or salt of EDTA at a concentration of between 0.01 and 10%, between 0.05% and 5%, or at a concentration of between 0.1% and 1%). In certain embodiments, for example, the salt of EDTA may be EDTA disodium salt dihydrate.

In certain embodiments, for example, the first detection reagent may comprise BSA (for example BSA at a concentration of between 0.1% and 30%, such as BSA at a concentration of between 0.5% and 20%, or at a concentration of between 0.1% and 10%).

In certain embodiments, for example, the first detection reagent may comprise one or more anti-microbial agent (for example one of the anti-microbial agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more anti-microbial agents may be selected from the group consisting of benzalkonium chloride, sodium azide, sodium fluoride, phenoxyethanol, sodium dehydroacetate, chlorobutanol, phenylethanol, 4-chloroxylenol, 1-hydroxypyridine-2-thione, paraben derivatives, glutaraldehyde, formaldehyde, nalidixic acid, sodium-2-pyridinethiol-1-oxide (sodium omadine™), Triadine™ 3, Triadine™ 10, various combinations of 5-chloro-2-methyl-4-isothiazolin-2-one, 2-methyl-4-isothiazolin-3-one, 5-bromo-5-nitro-1,3-dioxane, derivatives of each of these compounds, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more anti-microbial agents may be commercially available and selected from the group consisting of reagents comprising aqueous combinations of 5-chloro-2-methyl-4-methyl-4-isothiazolin-2-one and 2-methyl-4-isothiazolin-3-one (Supelco, under the trademark Proclin), for example, Proclin™ 150 reagent (Supelco, an aqueous mixture of 1.15% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.35% of 2-methyl-4-isothiazolin-3-one), ProClin™ 300 reagent (Supelco, a mixture of 2.3% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.7% of 2-methyl-4-isothiazolin-3-one in a solvent consisting of a modified glycol and alkyl carboxylate), Proclin™ 5000 reagent (Supelco, 2-methyl-4-isothiazolin-3-one in a dipropylene glycol solvent), Bronidox® L reagent (Cognis Corporation, biocide 5-bromo-5-nitro-1,3-dioxane), or a combination of two or more of the foregoing. In certain embodiments, for example, the first detection reagent may comprise a combination of two or more anti-microbial agents in any ratio effective to combat microbial growth. In certain embodiments, for example, the one or more anti-microbial agents may comprise benzalkonium chloride. In certain embodiments, for example, the one or more anti-microbial agents may comprise ProClin™ 300 reagent (for example ProClin™ 300 reagent at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%). In certain embodiments, for example, the one or more anti-microbial agents may comprise a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (for example the mixture at a concentration of between 0.01% and 10%, between 0.05% and 5%, or at a concentration of between 0.1% and 1%).

In certain embodiments, for example, the first detection reagent may comprise one or more blocking agents. In certain embodiments, for example, the blocking agent may be an interference blocker at a concentration of between 0.01% and 10%, between 0.05% and 5%, or at a concentration of between 0.1% and 1%.

In certain embodiments, for example, the first detection reagent may comprise water, sodium phosphate (dibasic), potassium phosphate (monobasic), NaCl, KCl, EDTA disodium salt dihydrate, BSA, an interference blocker, an anti-microbial agent (or a mixture of anti-microbial agents), and one or more first detection reagents (for example one or more tagged antibodies that each is specific to an analyte). In certain embodiments, for example, the first detection reagent may comprise: water at a concentration between 90% and 100%, sodium phosphate (dibasic) at a concentration between 1% to 10%, potassium phosphate (monobasic) at a concentration between 0.01% and 0.1%, NaCl at a concentration between 0.1% and 1%, KCl at a concentration of between 0.01% and 0.1%, EDTA disodium salt dihydrate at a concentration of between 0.1% and 1%, BSA at a concentration of between 1% and 10%, interference blocker at a concentration of between 0.1% and 1.0%, an anti-microbial agent at a concentration between 0.1% and 1%, an anti-human NF-L mouse IgG antibody at a concentration between 0.01% and 0.1%), a Tau antibody coupled with biotin at a concentration between 0.01% and 0.1%), an anti-human UCH L1 mouse IgG antibody at a concentration between 0.01% and 0.1%), and an anti-human GFAP mouse IgG antibody at a concentration between 0.01% and 0.1%).

In certain embodiments, for example the second detection reagent may comprise an enzyme conjugate (for example streptavidin-β-galactosidase (SBG)). In certain embodiments, for example, the second detection reagent may comprise an aqueous solution (for example a solution that may contain 90-100% water). In certain embodiments, for example, the second detection reagent may comprise a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of components selected from the group consisting of one or more buffers (or a buffering system) (for example phosphate buffer), one or more ions (for example Na⁺, K⁺, Mg²⁺ and/or Cl⁻ ions), one or more ionic salts (for example NaCl, MgCl₂ and KCl), one or more complexing agents (for example ethylenediaminetetraacetic acid (EDTA)), BSA, Tween-20, one or more enzyme conjugates (for example SBG) and one or more anti-microbial agents (for example a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone).

In certain embodiments, for example, the second detection reagent may comprise one or more buffers, or a buffering system (for example one or more of the buffers or buffering systems disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more buffers may be selected from the group consisting of citrate buffers, phosphate buffers, borate buffers, tris(hydroxymethyl)aminomethane (Tris) buffers, barbital buffers, bicarbonates, as well as Good buffers (non-toxic to cells; not absorbed through cell membranes and feature pKa values at or near physiological pH) such as but not limited to N,N′-bis(2-hydroxyethyl)glycine (BIC IN), 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1,3-propanediol (BISTRIS), 2-(cyclohexylamino)ethane-2-sulfonic acid (CHES), N-2-(hydroxyethyl)piperazine-N′-2-ethanesulfonic acid (HEPES), N-(2-hydroxyethyl)piperazine-N′-3-propanesulfonic acid (HEPPS), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), piperazine-N,N′-bis(2-ethanesulfonic acid) (PIPES), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), and N-tris(hydroxymethyl)methylglycine (TRICINE), or a combination of two or more of the foregoing. In certain embodiments, for example, the second detection reagent may comprise a buffering system comprising a combination of buffers. In certain embodiments, for example, the RGP reagent may contain a phosphate buffer (for example phosphate at a concentration of between 10 mM and 100 mM, such as phosphate at a concentration in the range of between 30 mM and 70 mM, or 50 mM, or sodium phosphate (dibasic) at a concentration of between 0.1% and 20%, such as sodium phosphate (dibasic) at a concentration of between 0.5% and 10%, or at a concentration of between 1% and 5%, and potassium phosphate (monobasic) at a concentration of between 0.05% and 20%, such as potassium phosphate (monobasic) at a concentration of between 0.1% and 10% or at a concentration of between 0.5% and 2%).

In certain embodiments, for example, the second detection reagent may comprise one or more ions (for example one or more of the ions disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ions may be selected from the group consisting of Li⁺, Na⁺, K⁺, Mg2⁺, Ca2⁺, Cu2⁺, Mn2⁺, Fe2⁺, Fe3⁺, NH4⁺, Cl⁻, Br⁻, carbonate, hydrogen carbonate, hydrogen sulfate, hydrogen sulfite, sulfate, sulfite, monohydrogen phosphate, dihydrogen phosphate, nitrate, nitrite, permanganate, silicate, sulphates, pyrosulphates, pyrophosphates, citrates, cacodylates and other suitable ions. In certain embodiments, for example, the one or more ions may comprise Cl⁻ (for example Cl⁻ at a concentration of between 100 mM and 200 mM, such as Cl⁻ at a concentration in the range of between 120 mM and 160 mM, or 141.7 mM). In certain embodiments, for example, the one or more ions may comprise Na⁺ (for example Na⁺ at a concentration of between 100 mM and 200 mM, such as Na⁺ at a concentration in the range of between 120 mM and 160 mM, or 137 mM). In certain embodiments, for example, the one or more ions may comprise K⁺ (for example K⁺ at a concentration of between 1 mM and 5 mM, such as K⁺ at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM).

In certain embodiments, for example, the ions may form one or more ionic salts (for example one or more of the ionic salts disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ionic salts may be selected from the group consisting of KCl, NaCl, MgCl₂, KH2PO4, K2HPO4, NaH2PO4, Na2HPO4, NaHCO3 and other suitable ionic salts. In certain embodiments, for example, the one or more ionic salts may comprise KCl (for example KCl at a concentration of between 1 mM and 5 mM, such as KCl at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM, or KCl at a concentration of 0.01-10%, such as KCl at a concentration of between 0.05% and 5%, or at a concentration of between 0.1% and 1%). In certain embodiments, for example, the one or more ionic salts may comprise NaCl (for example NaCl at a concentration of between 100 mM and 200 mM, such as NaCl at a concentration in the range of between 120 mM and 160 mM, or 137 mM, or NaCl at a concentration of between 0.01% and 10%, such as NaCl at a concentration of between 0.05% and 5%, or at a concentration of 0.1% and 1%). In certain embodiments, for example, the one or more ionic salts may comprise MgCl₂ (for example MgCl₂ at a concentration of between 0.1 mM and 5 mM, such as MgCl₂ at a concentration in the range of between 0.5 mM and 2.5 mM, or 1 mM, or MgCl₂ at a concentration of between 0.01% and 10%, such as MgCl₂ at a concentration of between 0.05% and 5%, or at a concentration of 0.1% and 1%).

In certain embodiments, for example, the second detection reagent may comprise one or more complexing agents that are capable of forming a complex with a metal ion (for example one of the complexing agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more complexing agents may be selected from the group consisting of EDTA, deferoxamine (DESFERAL), NTA, β-alaninediacetic acid (β-ADA), diethylenetriaminepentaacetic acid (DTPA), diethylenetriaminepentakis-methylenephosphonic acid (DTPMP), nitrilotriacetic acid (NTA), N-bis[2-1,2-dicarboxyethoxy)ethyl]glycine (BCA5), N-bis[2-1,2-dicarboxyethoxy)ethyl]aspartic acid (BCA6), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), gluconic acid and tetracis(2-hydroxypropyl)ethylenediamine (THPED), other suitable complexing agents, or a combination of two or more of the foregoing. In certain embodiments, for example, the complexing agent may comprise EDTA or a salt of EDTA (for example EDTA or salt of EDTA at a concentration of between 1 mM and 50 mM, of between 1 mM and 10 mM, or at a concentration of 5 mM, or EDTA or salt of EDTA at a concentration of between 0.01 and 10%, between 0.05% and 5%, or at a concentration of between 0.1% and 1%). In certain embodiments, for example, the salt of EDTA may be EDTA disodium salt dihydrate.

In certain embodiments, for example, the second detection reagent may comprise BSA (for example BSA at a concentration of between 0.1% and 30%, such as BSA at a concentration of between 0.5% and 20%, or at a concentration of between 0.1% and 10%).

In certain embodiments, for example, the second detection reagent may comprise tween 20 (for example tween 20 at a concentration of between 0.01% and 10%, such as tween 20 at a concentration of between 0.05% and 5%, or at a concentration of between 0.1% and 1%).

In certain embodiments, for example, the second detection reagent may comprise one or more enzyme conjugates. In certain embodiments, for example, the enzyme conjugate may be SBG (for example SBG at a concentration of between 0.001% and 1%, such as SBG at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%).

In certain embodiments, for example, the second detection reagent may comprise one or more anti-microbial agent (for example one of the anti-microbial agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more anti-microbial agents may be selected from the group consisting of benzalkonium chloride, sodium azide, sodium fluoride, phenoxyethanol, sodium dehydroacetate, chlorobutanol, phenylethanol, 4-chloroxylenol, 1-hydroxypyridine-2-thione, paraben derivatives, glutaraldehyde, formaldehyde, nalidixic acid, sodium-2-pyridinethiol-1-oxide (sodium omadine™), Triadine™ 3, Triadine™ 10, various combinations of 5-chloro-2-methyl-4-isothiazolin-2-one, 2-methyl-4-isothiazolin-3-one, 5-bromo-5-nitro-1,3-dioxane, derivatives of each of these compounds, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more anti-microbial agents may be commercially available and selected from the group consisting of reagents comprising aqueous combinations of 5-chloro-2-methyl-4-methyl-4-isothiazolin-2-one and 2-methyl-4-isothiazolin-3-one (Supelco, under the trademark Proclin), for example, Proclin™ 150 reagent (Supelco, an aqueous mixture of 1.15% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.35% of 2-methyl-4-isothiazolin-3-one), ProClin™ 300 reagent (Supelco, a mixture of 2.3% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.7% of 2-methyl-4-isothiazolin-3-one in a solvent consisting of a modified glycol and alkyl carboxylate), Proclin™ 5000 reagent (Supelco, 2-methyl-4-isothiazolin-3-one in a dipropylene glycol solvent), Bronidox® L reagent (Cognis Corporation, biocide 5-bromo-5-nitro-1,3-dioxane), or a combination of two or more of the foregoing. In certain embodiments, for example, the RGP reagent may comprise a combination of two or more anti-microbial agents in any ratio effective to combat microbial growth. In certain embodiments, for example, the one or more anti-microbial agents may comprise benzalkonium chloride. In certain embodiments, for example, the one or more anti-microbial agents may comprise ProClin™ 300 reagent (for example ProClin™ 300 reagent at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%). In certain embodiments, for example, the one or more anti-microbial agents may comprise a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (for example the mixture at a concentration of between 0.01% and 5%, between 0.05% and 2%, or at a concentration of between 0.1% and 1%).

In certain embodiments, for example, the second detection reagent may comprise water, sodium phosphate (dibasic), potassium phosphate (monobasic), NaCl, KCl, EDTA disodium salt dihydrate, BSA, Tween 20, MgCl₂, an enzyme conjugate and an anti-microbial agent (or a mixture of anti-microbial agents). In certain embodiments, for example, the second detection reagent may comprise: water at a concentration between 90% and 100%, sodium phosphate (dibasic) at a concentration between 1% and 5%, potassium phosphate (monobasic) at a concentration between 0.5% and 2%, NaCl at a concentration between 0.1% and 1%, KCl at a concentration of between 0.1% and 1%, MgCl₂ at a concentration between 0.1% and 1%, EDTA disodium salt dihydrate at a concentration between 0.1% and 1%, BSA at the concentration of between 1% and 10%, tween 20 at a concentration of between 0.1% and 1%, an enzyme conjugate at a concentration of between 0.01% and 0.1%, and an anti-microbial agent at a concentration between 0.1% and 1%.

In certain embodiments, for example the third detection reagent may comprise a fluorogenic enzyme substrate (for example resorufin b-galactopyranoside (RGP)). In certain embodiments, for example, the third detection reagent may comprise aqueous solution (for example a solution that may contain 90-100% water). In certain embodiments, for example, the third detection reagent may comprise a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of components selected from the group consisting of one or more buffers (or a buffering system) (for example phosphate buffer), one or more ions (for example Na⁺, K⁺ and/or Cl− ions), one or more ionic salts (for example NaCl and KCl), Pluronic™ F-127, resorufin b-galactopyranoside, and one or more anti-microbial agents (for example a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone).

In certain embodiments, for example, the third detection reagent may comprise one or more buffers, or a buffering system (for example one or more of the buffers or buffering systems disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more buffers may be selected from the group consisting of citrate buffers, phosphate buffers, borate buffers, tris(hydroxymethyl)aminomethane (Tris) buffers, barbital buffers, bicarbonates, as well as Good buffers (non-toxic to cells; not absorbed through cell membranes and feature pKa values at or near physiological pH) such as but not limited to N,N′-bis(2-hydroxyethyl)glycine (BIC IN), 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1,3-propanediol (BISTRIS), 2-(cyclohexylamino)ethane-2-sulfonic acid (CHES), N-2-(hydroxyethyl)piperazine-N′-2-ethanesulfonic acid (HEPES), N-(2-hydroxyethyl)piperazine-N′-3-propanesulfonic acid (HEPPS), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), piperazine-N,N′-bis(2-ethanesulfonic acid) (PIPES), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), and N-tris(hydroxymethyl)methylglycine (TRICINE), or a combination of two or more of the foregoing. In certain embodiments, for example, the third detection reagent may comprise a buffering system comprising a combination of buffers. In certain embodiments, for example, the third detection reagent may contain a phosphate buffer (for example phosphate at a concentration of between 10 mM and 100 mM, such as phosphate at a concentration in the range of between 30 mM and 70 mM, or 50 mM, or sodium phosphate (dibasic) at a concentration of between 0.01% and 5%, such as sodium phosphate (dibasic) at a concentration of between 0.05% and 1%, or at a concentration of between 0.1% and 0.5%, and potassium phosphate (monobasic) at a concentration of between 0.001% and 1%, such as potassium phosphate (monobasic) at a concentration of between 0.005% and 0.5% or at a concentration of between 0.01% and 0.1%).

In certain embodiments, for example, the third detection reagent may comprise one or more ions (for example one or more of the ions disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ions may be selected from the group consisting of Li⁺, Na⁺, K⁺, Mg2⁺, Ca2⁺, Cu2⁺, Mn2⁺, Fe2⁺, Fe3⁺, NH4⁺, Cl⁻, Br⁻, carbonate, hydrogen carbonate, hydrogen sulfate, hydrogen sulfite, sulfate, sulfite, monohydrogen phosphate, dihydrogen phosphate, nitrate, nitrite, permanganate, silicate, sulphates, pyrosulphates, pyrophosphates, citrates, cacodylates and other suitable ions. In certain embodiments, for example, the one or more ions may comprise Cl⁻ (for example Cl⁻ at a concentration of between 100 mM and 200 mM, such as Cl⁻ at a concentration in the range of between 120 mM and 160 mM, or 141.7 mM). In certain embodiments, for example, the one or more ions may comprise Na⁺ (for example Na⁺ at a concentration of between 100 mM and 200 mM, such as Na⁺ at a concentration in the range of between 120 mM and 160 mM, or 137 mM). In certain embodiments, for example, the one or more ions may comprise K⁺ (for example K⁺ at a concentration of between 1 mM and 5 mM, such as K⁺ at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM)

In certain embodiments, for example, the ions may form one or more ionic salts (for example one or more of the ionic salts disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ionic salts may be selected from the group consisting of KCl, NaCl, MgCl₂, KH2PO4, K2HPO4, NaH2PO4, Na2HPO4, NaHCO3 and other suitable ionic salts. In certain embodiments, for example, the one or more ionic salts may comprise KCl (for example KCl at a concentration of between 1 mM and 5 mM, such as KCl at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM, or KCl at a concentration of 0.001-1%, such as KCl at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%). In certain embodiments, for example, the one or more ionic salts may comprise NaCl (for example NaCl at a concentration of between 100 mM and 200 mM, such as NaCl at a concentration in the range of between 120 mM and 160 mM, or 137 mM, or NaCl at a concentration of between 0.01% and 10%, such as NaCl at a concentration of between 0.05% and 5%, or at a concentration of 0.1% and 1%).

In certain embodiments, for example, the third detection reagent may comprise Pluronic™ F-127 (for example Pluronic™ F-127 at a concentration of 0.001-1%, such as Pluronic™ F-127 at a concentration of between 0.005% and 0.5%, or at a concentration of between 0.01% and 0.1%).

In certain embodiments, for example, the third detection reagent may comprise resorufin b-galactopyranoside (for example resorufin b-galactopyranoside at a concentration of 0.0001-0.1%, such as resorufin b-galactopyranoside at a concentration of between 0.0005% and 0.05%, or at a concentration of between 0.001% and 0.01%).

In certain embodiments, for example, the third detection reagent may comprise one or more anti-microbial agent (for example one of the anti-microbial agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more anti-microbial agents may be selected from the group consisting of benzalkonium chloride, sodium azide, sodium fluoride, phenoxyethanol, sodium dehydroacetate, chlorobutanol, phenylethanol, 4-chloroxylenol, 1-hydroxypyridine-2-thione, paraben derivatives, glutaraldehyde, formaldehyde, nalidixic acid, sodium-2-pyridinethiol-1-oxide (sodium omadine™), Triadine™ 3, Triadine™ 10, various combinations of 5-chloro-2-methyl-4-isothiazolin-2-one, 2-methyl-4-isothiazolin-3-one, 5-bromo-5-nitro-1,3-dioxane, derivatives of each of these compounds, or a combination of two or more of the foregoing. In certain embodiments, for example, the one or more anti-microbial agents may be commercially available and selected from the group consisting of reagents comprising aqueous combinations of 5-chloro-2-methyl-4-methyl-4-isothiazolin-2-one and 2-methyl-4-isothiazolin-3-one (Supelco, under the trademark Proclin), for example, Proclin™ 150 reagent (Supelco, an aqueous mixture of 1.15% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.35% of 2-methyl-4-isothiazolin-3-one), ProClin™ 300 reagent (Supelco, a mixture of 2.3% of 5-chloro-2-methyl-4-isothiazolin-3-one and 0.7% of 2-methyl-4-isothiazolin-3-one in a solvent consisting of a modified glycol and alkyl carboxylate), Proclin™ 5000 reagent (Supelco, 2-methyl-4-isothiazolin-3-one in a dipropylene glycol solvent), Bronidox® L reagent (Cognis Corporation, biocide 5-bromo-5-nitro-1,3-dioxane), or a combination of two or more of the foregoing. In certain embodiments, for example, the third detection reagent may comprise a combination of two or more anti-microbial agents in any ratio effective to combat microbial growth. In certain embodiments, for example, the one or more anti-microbial agents may comprise benzalkonium chloride. In certain embodiments, for example, the one or more anti-microbial agents may comprise ProClin™ 300 reagent (for example ProClin™ 300 reagent at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%). In certain embodiments, for example, the one or more anti-microbial agents may comprise a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (for example the mixture at a concentration of between 0.01% and 5%, between 0.05% and 1%, or at a concentration of between 0.1% and 0.5%).

In certain embodiments, for example, the third detection reagent may comprise water, sodium phosphate (dibasic), potassium phosphate (monobasic), NaCl, KCl, Pluronic™ F-127, resorufin b-galactopyranoside and an anti-microbial agent (or a mixture of anti-microbial agents). In certain embodiments, for example, the third detection reagent may comprise: water at a concentration between 90% and 100%, sodium phosphate (dibasic) at a concentration between 0.1% to 0.5%, potassium phosphate (monobasic) at a concentration between 0.01% and 0.1%, NaCl at a concentration between 0.1% and 1%, KCl at a concentration of between 0.01% and 0.1%, Pluronic™ F-127 at a concentration of between 0.01% and 0.1%, resorufin b-galactopyranoside at a concentration of between 0.001% and 0.01%, and an anti-microbial agent at a concentration between 0.1% and 0.5%.

In certain embodiments, for example, the diluent may comprise a saline solution (for example a phosphate buffered saline solution). In certain embodiments, for example, the diluent may comprise one or more buffers (for example one or more of the buffers disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the diluent may comprise one or more ionic salts (for example one or more of the ionic salts disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more ionic salts may comprise KCl (for example KCl at a concentration of between 1 mM and 5 mM, such as KCl at a concentration in the range of between 2 mM and 3 mM, or 2.7 mM). In certain embodiments, for example, the diluent may comprise one or more blocking agents such as a blocking agent configured to prevent non-specific binding to an assay surface such as a microtiter well surface (for example one of the blocking agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more blocking agents may comprise bovine serum albumin (BSA) (for example BSA at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 2%). In certain embodiments, for example, the diluent may comprise one or more heterophile antibody blocking agents (for example one or more of the heterophile antibody blocking agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more heterophile antibody blocking agents may comprise Superchemiblock® (for example Superchemiblock® at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.05%). In certain embodiments, for example, the diluent may comprise one or more sugars (for example one or more of the sugars disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more sugars may comprise dextrose (for example dextrose at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.06%). In certain embodiments, for example, the diluent may comprise bovine gamma-globulin (BGG) (for example BGG at a concentration of between 0.005% and 0.05% (for example 0.02%), between 0.05% and 0.5%, between 0.5% and 1%, between 1% and 5%, or at a concentration of 0.01%). In certain embodiments, for example, the diluent may comprise urea (for example urea at a concentration of between 0.5 mM and 100 mM (for example 10 mM), between 1 mM and 20 mM, between 1 mM and 10 mM, or at a concentration of between 3 mM and 7 mM). In certain embodiments, for example, the diluent may comprise one or more detergents (for example one or more of the detergents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the one or more detergents may comprise Triton X-100 (for example Triton X-100 at a concentration of between 0.005% and 2% (for example 0.5%), between 0.1% and 1%, or the diluent may comprise Triton X-100 at a concentration of between 0.25% and 0.75%). In certain embodiments, for example, the diluent may comprise a surfactant (for example one of the surfactants disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the surfactant may comprise an ionic surfactant. In certain embodiments, for example, the surfactant may comprise a nonionic surfactant. In certain embodiments, for example, the surfactant may comprise a glycidyl surfactant (for example 10G surfactant (for example 10G surfactant at a concentration of between 0.01% and 1%, or 0.1%)). In certain embodiments, for example, the diluent may comprise a human anti-mouse antibody (HAMA) blocker (for example one of the HAMA blockers disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the HAMA blocker may comprise TRU block (for example TRU block at a concentration of between 1 mcg/mL and 100 mcg/mL, or 10 mcg/mL). In certain embodiments, for example, the diluent may comprise a complexing agent (for example one of the complexing agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the complexing agent may comprise ethylenediaminetetraacetic acid (EDTA) or a salt of EDTA (for example EDTA or salt of EDTA at a concentration of between 1 mM and 50 mM, of between 1 mM and 10 mM, or 5 mM). In certain embodiments, for example, the diluent may comprise an anti-microbial agent (for example one of the complexing agents disclosed herein or in one of the INCORPORATED REFERENCES). In certain embodiments, for example, the anti-microbial agent may comprise benzalkonium chloride. In certain embodiments, for example, the diluent may have a pH of between 2.5 and 10 (for example a pH in the range of 5 and 9, in the range of 7 to 8, a pH of 7.4, or an approximately neutral pH). In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, KCl, BSA, 10G Surfactant, TRU block, EDTA, and an anti-microbial agent. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, KCl at a concentration of between 3 mM and 5 mM, BSA at a concentration of between 1% and 3%, 10G surfactant at a concentration of between 0.05% and 0.15%, TRU block at a concentration of between 5 mcg/mL and 15 mcg/mL, EDTA or salt of EDTA at a concentration of between 3 mM and 7 mM, and an anti-microbial agent, wherein the diluent may have a pH of between 7 and 8. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, KCl at a concentration of 2.7 mM, BSA at a concentration of 2%, 10G surfactant at a concentration of 0.1%, TRU block at a concentration of 10 mcg/mL, EDTA or salt of EDTA at a concentration of 5 mM, and an anti-microbial agent, wherein the diluent may have a pH of 7.4. In certain embodiments, for example, the diluent may comprise: phosphate buffered saline, dextrose at a concentration of 0.06%, BSA at a concentration of 0.02%, BGG at a concentration of 0.01%, urea at a concentration of 5 mM, Triton X-100 at a concentration of 0.5%, TRU block at a concentration of 10 mcg/mL, Superchemiblock at a concentration of 0.05%, and an anti-microbial agent, wherein the diluent may have a pH of 7.4

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of a panel of biomarkers in a sample comprises performing an assay on a sample derived from a human and determining a measure of the concentration of NF-L and at least one other biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, in the sample collected from the patient. Certain embodiments, for example, may provide an assay having an LOQ of no greater than 0.1 pg/mL for Tau protein, no greater than 1 pg/mL for NF-L and GFAP, and no greater than 5 pg/mL for UCH-L1.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may be used for determining a measure of the concentration of a panel of biomarkers in a sample comprises a plurality of capture objects, each having a binding surface comprising a plurality of capture components, a plurality of a first type of binding ligand having affinity for NF-L, and a plurality of a second type of binding ligand and a third type of binding ligand having affinity for at least two other biomarkers selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Certain embodiments may provide, for example, an assay indicated by a traumatic event, comprising: i) providing a liquid sample, the liquid sample derived from a dried sample of physiological fluid taken within 24 hours of the event; ii) exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for one or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) binding at least one capture object of the plurality of capture objects to at least one biomarker of the one or more biomarkers; iv) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the one or more biomarkers; and v) quantifying concentrations of the one or more biomarkers, at least one of the concentrations indicative of a neurological condition (for example a neural injury or a degenerative neurological disease) at a level of less than 1 picomole/L.

Certain embodiments may provide, for example, a method to detect a neurological condition (for example a neural injury or a degenerative neurological disease) in a subject, comprising: i) performing the assay; ii) calculating at least one classification value based on a classification model of the concentrations; and iii) assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a method to determine when a neural injury occurred, comprising: i) providing a liquid sample derived from a dried sample comprising physiological fluid, wherein the dried sample is at least 2 months old; and ii) quantifying at least one parameter for at least one biomarker in the liquid sample, the at least one biomarker indicative of the neural injury at a concentration in the liquid sample of less than 1 picomole/L.

Certain embodiments may provide, for example, a single-sample test for a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) providing a liquid sample derived from a single sample of dried capillary blood; ii) obtaining, via digital immunoassay, a concentration in the liquid sample of NF-L; iii) calculating at least one classification value based on a classification model of the concentration of NF-L; and iv) assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a single-sample test for excluding a neurological condition (for example a neural injury or a degenerative neurological disease) as a result of a medical procedure, comprising: i) providing a liquid sample derived from a single sample of dried physiological fluid, the single sample of dried physiological fluid obtained from a subject after a medical procedure is performed on the subject; ii) obtaining, via digital immunoassay of at least a portion of the liquid sample, a concentration of NF-L; iii) calculating at least one classification value for the subject based on a classification model of the concentration; and iv) assigning a low risk of the neurological condition (for example a neural injury or a degenerative neurological disease) if the at least one classification value is less than at least one threshold value.

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) providing at least one liquid sample derived from at least one sample of dried capillary blood, the at least one sample of dried capillary blood obtained from a subject during a 10-hour time window; ii) obtaining, via at least one digital immunoassay of at least a portion of the at least one liquid sample, a concentration of NF-L; iii) calculating at least one classification value for the subject based on a classification model of the concentration; and iv) assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a test for a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) providing a liquid sample derived from a sample of dried physiological fluid from a subject; ii) obtaining, via a digital immunoassay of at least a portion of the liquid sample, a concentration for at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) normalizing the concentration based at least on a sample age of the dried physiological fluid; iv) calculating at least one classification value for the subject based on a classification model of the normalized concentration; and v) assigning a risk of the neurological condition (for example a neural injury or a degenerative neurological disease), comprising: comparing the at least one classification value to at least one threshold value.

Certain embodiments may provide, for example, a method for detecting a neurological condition (for example a neural injury or a degenerative neurological disease) using dried capillary blood, comprising: i) providing a liquid sample derived from dried capillary blood; ii) diluting the liquid sample to adjust the liquid sample to within a working range in a digital immunoassay, the working range comprising: a) at least one biomarker at a concentration in the diluted liquid sample that is greater than a corresponding at least one limit of quantification of the digital immunoassay; and b) at least one threshold indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) that is greater than the at least one corresponding limit of quantification; and iii) quantifying the at least one biomarker concentration via the digital immunoassay.

Certain embodiments may provide, for example, a method for detecting a neurological condition (for example a neural injury or a degenerative neurological disease) using dried capillary blood, comprising: i) providing a liquid sample derived from dried capillary blood; ii) diluting a portion of the liquid sample to align at least one biomarker concentration in the diluted portion of the liquid sample with a classification model for determining a risk of the neurological condition (for example a neural injury or a degenerative neurological disease); and iii) quantifying the at least one biomarker concentration via a digital immunoassay.

Certain embodiments may provide, for example, a dual-assay method to detect a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) quantifying NF-L in a first fluid sample, the first fluid sample derived from dried capillary blood of a neonate; ii) determining that the quantified NF-L exceeds a predetermined threshold; and iii) performing, in response to the determining, at least one digital immunoassay on a second fluid sample derived from the neonate to quantify at least one biomarker for the neurological condition (for example a neural injury or a degenerative neurological disease), the at least one biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Certain embodiments may provide, for example, a method to screen for a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) providing a first fluid sample derived from dried capillary blood, the dried capillary blood obtained from a subject following a medical procedure on the subject; ii) quantifying a first component present in the first fluid sample; iii) computing a dilution factor based on the quantified first component; iv) diluting a second fluid sample by the dilution factor, the second fluid sample derived from the dried capillary blood; and v) quantifying at least one biomarker in the diluted second fluid sample via at least one digital immunoassay, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Certain embodiments may provide, for example, a method to screen for a neurological condition (for example a neural injury or a degenerative neurological disease), comprising: i) providing a first series of fluid samples derived from a series of dried capillary blood samples, the series of dried capillary blood samples obtained from a subject at predetermined time intervals following a medical procedure on the subject; ii) quantifying concentrations of a first component present in the first series of fluid samples; iii) computing a series of dilution factors based on the quantified concentrations; iv) diluting a second series of fluid samples based on the series of dilution factors, the second series of fluid samples derived from the series of dried capillary blood samples; and v) quantifying concentrations of at least one biomarker in the diluted second series of fluid samples via a series of digital immunoassay, the at least one biomarker selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Certain embodiments may comprise, for example, a method to test for a suspected neural injury in a subject, comprising: i) eluting a dried sample of physiological fluid in a diluent to form a liquid sample, the physiological fluid obtained from the subject within 24 hours of an occurrence of the suspected neural injury; ii) exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for one or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) binding at least one capture object of the plurality of capture objects to at least one molecule of the one or more biomarkers; iv) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the one or more biomarkers; and v) obtaining one or more concentrations of the one or more biomarkers in the liquid sample.

A. In certain embodiments, for example, the suspected neural injury may be a suspected traumatic brain injury. In certain embodiments, for example, the suspected neural injury may be collateral to childbirth the subject. In certain embodiments, for example, the dried sample of physiological fluid may comprise one or more dried spots of capillary blood. In certain embodiments, for example, the diluent may comprise human IgG at a concentration of between 1 mg/mL and 10 mg/mL. In certain embodiments, for example, the one or more biomarkers may be at least two biomarkers and the obtained one or more concentrations is at least two concentrations, wherein the obtaining comprises: i) calculating at least two measured parameters based on Poisson and/or Gaussian distribution analysis of the exposed plurality of capture objects; and ii) inputting the at least two measured parameters into a multivariate calibration model. In certain embodiments, for example, the multivariate calibration model may be derived from results of a series of multiplex calibration immunoassays. In certain embodiments, for example, the multivariate calibration model may provide a series of comparative concentration values for the at least two biomarkers that are between 80% and 140% proportional when the liquid sample is diluted between 4 times and 64 times with the diluent. In certain embodiments, for example, at least one of the series of multiplex calibration immunoassays may comprise a multiplex assay performed on a calibration solution containing the at least two biomarkers. In certain embodiments, for example, at least one of the at least two concentrations may be indicative of the suspected neural injury at a level of less than 1 picomole/L.

Certain embodiments may comprise, for example, a test for a neurological condition in a subject, comprising: i) providing a liquid sample derived from a sample of dried physiological fluid taken from the subject; ii) obtaining, via a multiplex immunoassay, concentrations of at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample; iii) calculating at least one classification value based on a multivariate classification model using the obtained concentrations as inputs to the multivariate classification model; and iv) assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

A. In certain embodiments, for example, the neurological condition may be a neurodegenerative disease. In certain embodiments, for example, the multiplex immunoassay may be a digital assay. In certain embodiments, for example, the multiplex immunoassay may be a multiplex spotted well assay. In certain embodiments, for example, the multivariate classification model may predict the neurological condition with an ROC curve having an AUC of at least 0.85. In certain embodiments, for example, the multivariate classification model may predict the neurological condition with a true positive rate of at least 75% at a false positive rate of less than 25%. In certain embodiments, for example, the test may further comprise: determining whether a CT scan of the subject is positive or negative for the neurological condition prior to performing the multiplex immunoassay. In certain embodiments, for example, the at least one classification value may comprise a ratio of one of the obtained concentrations to a concentration of a reference component present in the liquid sample.

Certain embodiments may comprise, for example, a dual-sample test for a neurological condition in a subject, comprising: i) providing: a) a first liquid sample derived from a dried sample of a first physiological fluid taken from the subject at a first time; and b) a second liquid sample derived from a second physiological fluid (for example a dried physiological fluid or an undried physiological fluid such as liquid whole blood, plasma, serum, urine or saliva) taken from the subject at a second time; ii) performing: a) a first multiplex immunoassay to obtain first concentrations of at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample; and b) a second multiplex immunoassay to obtain second concentrations of the at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the second liquid sample; and iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the first concentrations and the second concentrations.

A. In certain embodiments, for example, the first time is prior to the second time, wherein the second physiological fluid is taken in response to a suspected occurrence of the neurological condition.

Certain embodiments may provide, for example, a multi-sample test for a neurological condition in a subject, comprising: i) providing: a) a first liquid sample derived from a dried sample of a first physiological fluid taken from the subject at a first time; and b) at least a second liquid sample derived from at least a second physiological fluid (for example a series of dried physiological fluid samples, a series of undried physiological fluid samples such as liquid whole blood, plasma, serum, urine or saliva, or a combination of dried and undried physiological fluid samples) taken from the subject at least a second time; ii) performing: a) a first multiplex immunoassay to obtain first concentrations of at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample; and b) at least a second multiplex immunoassay to obtain at least second concentrations of the at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least second liquid sample; and iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the first concentrations and the at least second concentrations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of a sample method.

FIG. 2 is a schematic depiction of a singleplex quantification method.

FIG. 3 is a schematic depiction of a multiplex quantification method.

FIG. 4 is an NF-L concentration curve obtained from a multiplex digital immunoassay of a dried blood spot sample.

FIG. 5 is a Tau protein concentration curve obtained from a multiplex digital immunoassay of a dried blood spot sample.

FIG. 6 is a GFAP protein concentration curve obtained from a multiplex digital immunoassay of a dried blood spot sample.

FIG. 7 is a UCH L1 protein concentration curve obtained from a multiplex digital immunoassay of a dried blood spot sample.

FIG. 8A is a NF-L immunoassay dose-response curve, according to certain embodiments.

FIG. 8B is NF-L concentration in plasma, matched serum, and CSF from healthy donors.

FIG. 9A is a Tau protein immunoassay dose-response curve.

FIG. 9B is Tau protein concentration in plasma, matched serum, and CSF from healthy donors.

FIG. 10A is a GFAP immunoassay dose-response curve.

FIG. 10B is GFAP concentration in plasma, matched serum, and CSF from healthy donors.

FIG. 11A is a UCH-L1 immunoassay dose-response curve.

FIG. 11B is UCH-L1 concentration in plasma, matched serum, and CSF from healthy donors.

FIG. 12 is a schematic depiction of a multiplex spotted well assay.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is based, generally, on the discovery that biomarkers collateral to neural function can be rapidly quantified from dried samples (even aged dried samples) of physiological fluids at very low concentrations (for example femtomolar) and used to help characterize the neural health of a subject, inclusive of detecting a neural condition, excluding a neural condition, predicting onset of a neural condition, and distinguishing between two or more neurological conditions that present similarly. Such an approach simplifies collection and storage of samples, reduces healthcare costs, and in some cases allows for personal collection without the need for supervision by a healthcare provider. The present disclosure is further specifically based, in part, on the discovery of multi-component calibrators and sample diluent formulations and preparation methods that improve the precision of biomarker measurements in dried samples. Moreover, these formulations and methods can be applied to a samples obtained from a plurality of individuals (for example a combination of healthy individuals and others suffering from one or more neurological conditions) to obtain data sets from which improved classification models are obtained. These models can be applied to single samples obtained proximate a time of elevated risk of neural injury (for example during or shortly after childbirth) to detect neural injury. Kits based on the formulations and methods disclosed herein enable a subject to benefit from these improved classification models.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, and/or systems for detecting, diagnosing, distinguishing, and/or excluding a neurological condition. In certain embodiments, for example, the neurological condition may comprise a disease. In certain embodiments, for example, the disease may be selected from the group consisting of Alzheimer's disease, motor neuron disease, frontotemporal dementia, HIV-associated dementia, progressive supranuclear palsy, Parkinson disease, Huntington's disease, Lewy Body dementia, dementia pugilistica, Creutzfeldt-Jakob disease, amyotrophic lateral sclerosis, transverse myelitis, MS, demyelination occurring after trauma to the brain or spinal cord, or a combination of two or more of the foregoing diseases.

In certain embodiments, for example, the neurological condition may comprise a condition resulting from an injury (for example traumatic brain injury). In certain embodiments, for example, the condition resulting from an injury may be selected from the group consisting of acute brain injury, spinal cord injury, peripheral nerve injury, ischaemic brain injury, traumatic brain injury (head trauma), traumatic spinal cord injury (or spinal cord trauma), stroke related injury, concussion (optionally including post-concussion syndrome), cerebral aneurism related injury, injury from general anoxia, hypoxia, hypoglycemia, hypotension, damage to retinal ganglion cells, a spinal cord injury (optionally including monoplegia, diplegia, paraplegia, hemiplegia and quadriplegia, or a combination of two or more of the foregoing), demyelination occurring after trauma to the brain or spinal cord, brain injuries secondary to seizures (for example seizures induced by radiation, exposure to ionizing or iron plasma, nerve agents, cyanide, toxic concentrations of oxygen, neurotoxicity due to CNS malaria or treatment with anti-malaria agents, trypanosomes, malarial pathogens, other CNS traumas, or a combination of two or more of the foregoing), injuries caused by procedures (for example procedures resulting from embole, hyperfusion, or hypoxia), or a combination of two or more of the foregoing conditions.

In certain embodiments, for example, the neurological condition may comprise a defect. In certain embodiments, for example, the defect may be selected from the group consisting of defects caused by defective tissues or cells of the nervous system, defects caused by defective tissues or cells that affect the nervous system (such as defective spine morphogenesis and defects in dendritic spine morphology), or a combination of two or more of the foregoing defects.

In certain embodiments, for example, the neurological condition may comprise a disorder. In certain embodiments, for example, the disorder may be selected from the group consisting of transverse myelitis, MS, demyelination occurring after trauma to the brain or spinal cord, memory loss, long term and short term memory disorders, learning disorders, autism, depression, benign forgetfulness, children learning disorders, learning disorders, attention deficit disorder, neuronal reaction to viral infection, brain damage, hereditary myelin disorder of the CNS, epilepsy, perinatal asphyxia, asphyxia, anoxia, status epilepticus, and stroke, concussion (including post-concussion syndrome), baldness (such as male pattern baldness), alopecia areata, addiction, clinical depression, neurofibromatosis, tuberous sclerosis, bipolar disorder, posttraumatic stress disorder, anxiety disorder, psychiatric disorders such as bi-polarism, schizophrenia and the like, narcolepsy/sleep disorders (optionally including circadian rhythm disorders, insomnia, narcolepsy, or a combination of two or more of the foregoing); severance of nerves or nerve damage, severance of the cerebrospinal nerve cord and any damage to brain or nerve cells, neurological deficits associated with AIDS, tics (for example Giles de la Tourette's syndrome), Huntington's chorea, schizophrenia, traumatic brain injury, tinnitus, neuralgia, especially trigeminal neuralgia, neuropathic pain, inappropriate neuronal activity resulting in neurodysthesias in diseases such as diabetes, MS and motor neuron disease, ataxias, muscular rigidity (spasticity), temporomandibular joint dysfunction, atypical parkinsonian disorders, Down's syndrome, or a combination of two or more of the foregoing disorders.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, and/or systems for detecting, diagnosing, distinguishing, and/or excluding a neurological condition. In certain embodiments, for example, the neurological condition may comprise MS. In certain embodiments, for example, the MS may comprise relapsing-remitting MS. In certain embodiments, for example, the MS may comprise primary progressive MS. In certain embodiments, for example, the MS may comprise progressive relapsing MS. In certain embodiments, for example, the MS may comprise secondary progressive MS.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, and/or systems for detecting, diagnosing, distinguishing, and/or excluding a neurological condition in a subject (for example a subject having symptoms indicative of the neurological condition or a subject having a history of the neurological condition or a related condition). In certain embodiments, for example, the methods, tests, protocol, assays, kits, and/or systems may comprise calculating at least one classification value based on a multivariate classification model of the concentrations of a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of biomarkers (for example two or more of NF-L, Tau, GFAP or UCH L1) in a liquid sample. In certain embodiments, for example, the methods, tests, protocol, assays, kits, and/or systems may comprise assigning a risk of having (or developing) neurological condition, comprising: comparing the at least one classification value to at least one threshold value.

In certain embodiments, for example, the classification model may be a statistical model. In certain embodiments, for example, the classification model may be a regression, linear regression, quadratic regression, polynomial regression, logistic regression, neural network, clustering model, principle component analysis, nearest neighbor classifier analysis, support vector machines, linear discriminant analysis, quadratic discriminant analysis, decision trees, genetic algorithm, classifier optimization using bagging, classifier optimization using boosting, classifier optimization using the Random Subspace Method, a projection pursuit, genetic programming, weighted voting, or a combination of two or more of the foregoing.

In certain embodiments, for example, the classification model may be a regression model (for example a logistic regression model). In certain embodiments, for example, the regression model may include at least one coefficient (for example 1 coefficient, 2 coefficients, or more than 2 coefficients) for at least two (for example each or all) of the biomarkers in a selected set of biomarkers (for example two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE). In certain embodiments, for example, the coefficients for the regression model may be determined using a maximum likelihood algorithm. In certain embodiments, for example, the regression may be a logistic regression. In certain embodiments, for example, the logistic regression may be a binary logistic regression.

In certain embodiments, for example, the classification model may be a neural network. In certain embodiments, for example, the neural network may be constructed for a selected set of biomarkers (for example two or more of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE). In certain embodiments, for example, the neural network may be a two-stage regression. In certain embodiments, for example, the neural network may be a two stage classification model. In certain embodiments, for example, the neural network may have a layered structure that includes a layer of input units connected by a layer of weights to a layer of output units. In certain embodiments, for example, the neural network may be a multilayer neural network. In certain embodiments, for example, the multilayer neural network may comprise input layer, at least one hidden layer, and an output layer. In certain embodiments, for example, a single bias layer may be connected to each layer other than the input layer.

In certain embodiments, for example, the classification model may be calibrated to determine the at least one threshold value at least based on one or more data sets. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from healthy individuals (and/or individuals who do not have a neurological condition nor a history of a neurological condition). In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals who have the neurological condition or a history of the neurological condition. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may comprise diagnostic results from a CT scan and/or an MRI scan. In certain embodiments, for example, the at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may comprise positive diagnostic results for the neural condition (for example CT-positive or MRI-positive results indicative of the neural condition). In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may comprise negative diagnostic results for the neural condition (for example CT-negative or MRI-negative results indicative of the absence of the neural condition). In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may comprise mixed diagnostic results for the neural condition (for example CT-negative/MRI-positive or CT-positive/MRI-negative results).

In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be obtained from individuals who may have been subject to two or more diagnostic methods (for example a CT scan and an MRI scan). In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals having positive results for the neurological condition in at least one diagnostic method. In certain embodiments, for example, at least a portion of the data set may (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) be derived from biospecimens from individuals having a positive CT scan and a positive MRI scan for the neurological condition. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals having a positive CT scan and a negative MRI scan for the neurological condition. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals having a negative MRI scan and a positive MRI scan for the neurological condition. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals having negative results for the neurological condition in the two or more diagnostic methods. In certain embodiments, for example, at least a portion of the data set (for example at least 10%, at least 20%, at least 30%, or at least 50% of the data set) may be derived from biospecimens from individuals having a negative MRI scan and a negative MRI scan for the neurological condition.

In certain embodiments, for example, the data set may be derived from biospecimens from at least 25 healthy controls (for example at least 40 healthy controls, at least 50 healthy controls, at least 75 healthy controls, at least 100 healthy controls, or the data set may be derived from biospecimens from at least 200 healthy controls. In certain embodiments, for example, the data set may be derived from biospecimens from at least 25 subjects exhibiting at least one indication from the neurological condition (for example at least 40 subjects, at least 50 subjects, at least 75 subjects, at least 100 subjects, or the data set may be derived from biospecimens from at least 200 subjects exhibiting at least one indication from the neurological condition.

In certain embodiments, for example, the neurological condition may comprise traumatic brain injury. In certain embodiments, for example, at least 10% (for example at least 20%, at least 30%, or at least 50%) of the data set may comprise data derived from biospecimens from subjects who have a Glasgow Coma Score of 3-8, a Glasgow Coma Score of 9-12, and/or a Glasgow Coma Score of 13-15. In certain embodiments, for example, the data set may be derived from biospecimens (for example at least 50 biospecimens, at least 75 biospecimens, at least 100 biospecimens, at least 125 biospecimens, at least 150 biospecimens, or at least 200 biospecimens) obtained from the TRACK-TBI pilot study. In certain embodiments, for example, the data set may be derived from biospecimens (for example at least 50 biospecimens, at least 75 biospecimens, at least 100 biospecimens, at least 125 biospecimens, at least 150 biospecimens, or at least 200 biospecimens) obtained from the Traumatic Head Injury Neuroimaging Classification study (NCT01132937).

In certain embodiments, for example, at least a portion of the data set may be derived from biospecimens from the subject. In certain embodiments, for example, at least a portion of the data set may be derived from biospecimens from the subject prior to developing (or prior to the detection of (for example by a healthcare provider)) symptoms indicative of the neurological condition, for example at least 5 minutes prior, at least 15 minutes prior to, at least 30 minutes prior to, at least 45 minutes prior to, at least 1 hour prior to, at least 2 hours prior to, at least 4 hours prior to, at least 6 hours prior to, at least 12 hours prior to, at least 24 hours prior to, at least 48 hours prior to, at least 72 hours prior to, at least 96 hours prior to, at least 1 week prior to, at least 2 weeks prior to, at least 3 weeks prior to, at least 4 weeks prior to, at least 5 weeks prior to, at least 6 weeks prior to, at least 8 weeks prior to, or at least 12 weeks prior to developing (or prior to the detection of (for example by a healthcare provider)) symptoms indicative of the neurological condition. In certain embodiments, for example, at least a portion of the data set may be derived from biospecimens from the subject subsequent to developing (or subsequent to the detection of (for example by a healthcare provider)) symptoms indicative of the neurological condition, for example at least 5 minutes subsequent to, at least 15 minutes subsequent to, at least 30 minutes subsequent to, at least 45 minutes subsequent to, at least 1 hour subsequent to, at least 2 hours subsequent to, at least 4 hours subsequent to, at least 6 hours subsequent to, at least 12 hours subsequent to, at least 24 hours subsequent to, at least 48 hours subsequent to, at least 72 hours subsequent to, at least 96 hours subsequent to, at least 1 week subsequent to, at least 2 weeks subsequent to, at least 3 weeks subsequent to, at least 4 weeks subsequent to, at least 5 weeks subsequent to, at least 6 weeks subsequent to, at least 8 weeks subsequent to, or at least 12 weeks subsequent to developing (or subsequent to the detection of (for example by a healthcare provider)) symptoms indicative of the neurological condition.

In certain embodiments, for example, the classification model may be at least partially characterized by an ROC curve. In certain embodiments, for example, the ROC curve may provide one or more parameters to evaluate the sensitivity and specificity of the results of the methods, tests, protocol, assays, kits, and/or systems for detecting, diagnosing, distinguishing, and/or excluding a neurological condition. In certain embodiments, for example, the classification model may be calibrated to determine the at least one threshold value at least based a preselected true positive rate (i.e., sensitivity) and/or a preselected false positive rate (i.e., 1-specificity). In certain embodiments, for example, the preselected true positive rate and/or preselected false positive rate may be selected from a point on the ROC curve. In certain embodiments, for example, the at least one threshold value may provide a true positive rate (for example a true positive rate measured from the ROC curve) of at least 60%, for example at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or the at least one threshold value may provide a true positive rate of 100%. In certain embodiments, for example, the at least one threshold value may provide a true positive rate of between 60% and 100%, for example between 60% and 95%, between 70% and 95%, between 70% and 90%, or at least one threshold value may provide a true positive rate of between 80% and 95%. In certain embodiments, for example, the at least one threshold value may provide a false positive rate (for example a false positive rate measured from the ROC curve) of less than 60%, for example less than 50%, less than 40%, less than 30%, less than 20%, or the at least one threshold value may provide a false positive rate of less than 10%. In certain embodiments, for example, the at least one threshold value may provide a false positive rate of between 10% and 80%, for example between 10% and 50%, between 10% and 40%, between 10% and 30%, between 20% and 50%, or the at least one threshold value may provide a false positive rate of between 20% and 40%. In certain embodiments, for example, the at least one threshold value may provide a true positive rate of at least 60% at a false positive rate of less than 20%, for example a true positive rate of at least 65% at a false positive rate of less than 20%, a true positive rate of at least 70% at a false positive rate of less than 20%, a true positive rate of at least 75% at a false positive rate of less than 20%, a true positive rate of at least 80% at a false positive rate of less than 20%, a true positive rate of at least 85% at a false positive rate of less than 20%, or the at least one threshold value may provide a true positive rate of at least a true positive rate of at least 90% at a false positive rate of less than 20%. In certain embodiments, for example, the at least one threshold value may provide a true positive rate of at least 60% at a false positive rate of less than 30%, for example a true positive rate of at least 65% at a false positive rate of less than 30%, a true positive rate of at least 70% at a false positive rate of less than 30%, a true positive rate of at least 75% at a false positive rate of less than 30%, a true positive rate of at least 80% at a false positive rate of less than 30%, a true positive rate of at least 85% at a false positive rate of less than 30%, or the at least one threshold value may provide a true positive rate of at least a true positive rate of at least 90% at a false positive rate of less than 30%. In certain embodiments, for example, the at least one threshold value may provide a true positive rate of at least 60% at a false positive rate of less than 50%, for example a true positive rate of at least 65% at a false positive rate of less than 50%, a true positive rate of at least 70% at a false positive rate of less than 50%, a true positive rate of at least 75% at a false positive rate of less than 50%, a true positive rate of at least 80% at a false positive rate of less than 50%, a true positive rate of at least 85% at a false positive rate of less than 50%, or the at least one threshold value may provide a true positive rate of at least a true positive rate of at least 90% at a false positive rate of less than 50%.

In certain embodiments, for example, the ROC curve may have an AUC of at least 0.95, for example at least 0.50, at least 0.55, at least 0.60, at least 0.65, at least 0.70, at least 0.75, at least 0.80, at least 0.85, at least 0.875, at least 0.90, or the ROC curve may have an AUC of at least 0.925. In certain embodiments, for example, the ROC curve may have an AUC of between 0.6 and 0.95, for example between 0.65 and 0.9, between 0.65 and 0.85, between 0.7 and 0.9, or the ROC curve may have an AUC of between 0.7 and 0.85.

Certain embodiments may provide, for example, methods, tests, protocol, assays (for example digital immunoassays), kits, or systems to quantify abnormal levels of one or more biomarkers present in a sample of dried physiological fluid taken from a subject. In certain embodiments, for example, the physiological fluid may be capillary blood. In certain embodiments, for example, a sample of capillary blood may be obtained from a finger prick or a heel prick and transferred directly to the specimen collection paper and dried. In certain embodiments, for example, the physiological fluid may be taken from a subject (for example an infant via a heel prick) following an event (for example an event comprising a medical procedure, or a potentially neural injury-inducing event). In certain embodiments, for example, the physiological fluid may be taken within 1 week following the event, for example within 36 hours following the event, within 24 hours, within 12 hours, within 11 hours, within 10 hours, within 9 hours, within 8 hours, within 7 hours, within 6 hours, within 5 hours, within 4 hours, within 3 hours, within 2 hours, within 1 hour, within 45 minutes, within 30 minutes, within 15 minutes, within 10 minutes, within 5 minutes, or the physiological fluid may be taken within 1 minute following the event. In certain embodiments, for example, the physiological fluid may be taken after at least 10 minutes following the event, for example at least 30 minutes following the event, at least 1 hour, at least 2 hours, at least 6 hours, at least 8 hours, at least 12 hours, at least 24 hours, at least 3 days, or the physiological fluid may be taken between after at least 7 days following the event. In certain embodiments, for example, the physiological fluid may be taken between 1 hour and 15 days following the event, for example between 1 hour and 2 days following the event, between 1 hour and 12 hours, between 6 hours and 3 days, or the physiological fluid may be taken between 6 hours and 10 days following the event.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may be limited to testing a single liquid sample derived from the sample of dried physiological fluid. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise testing multiple liquid samples derived from multiple samples of dried physiological fluid (for example samples taken from the subject at spaced time intervals). In certain embodiments, for example, multiple samples of physiological fluid may be taken (for example drawn or obtained using a heel prick) from a subject (and separately dried) at different times (for example a sequence of spaced times) during a predetermined time window. In certain embodiments, for example, between 2 and 10 physiological fluid samples (for example between 3 and 5 physiological fluid samples) may be taken from the subject during a time window of less than 20 days, for example during a time window of less than 10 days, less than 7 days, less than 100 hours, less than 48 hours, or less than 24 hours.

In certain embodiments, for example, the dried sample of physiological fluid may weigh less than 1 gram, for example less than 0.5 grams, less than 0.25 grams, less than 0.1 grams, less than 0.01 grams, less than 1 mg, less than 100 mcg, less than 10 mcg, less than 1 mcg, less than 0.1 mcg, or the dried sample of physiological fluid may weigh less than 0.01 mcg.

In certain embodiments, for example, the sample of physiological fluid (for example capillary blood) may be dried at a temperature of between 0° C. and 45° C., for example between 4° C. and 25° C. In certain embodiments, for example, the sample of capillary blood may be dried at ambient conditions. In certain embodiments, for example, the dried sample may be maintained (for example stored) at a temperature of between −20° C. and 25° C., for example at a temperature of between −20° C. and 0° C., 0° C. and 4° C., 4° C. and 15° C., or the dried sample may be maintained at a temperature of between 15° C. and 25° C. In certain embodiments, for example, the dried sample may be maintained (for example stored) under ambient conditions (for example ambient temperature and/or humidity). In certain embodiments, for example, the dried sample may be maintained at a relative humidity of less than 50%. In certain embodiments, for example, the dried sample may be stored for at least 1 month, for example for at least 2 months, at least 3 months, at least 6 months, at least 1 year, at least 2 years, between 1 month and 5 years, between 1 month and 3 months, between 1 month and 1 year, between 1 month and 2 years, between 1 month and 3 years, or between 1 month and 4 years. In certain embodiments, for example, the dried sample may be stored for at least 4 years, for example at least 5 years or at least 10 years.

In certain embodiments, for example, at least a portion of the dried sample may be reconstituted into liquid form and provided to perform a singleplex or multiplex digital immunoassay. In certain embodiments, for example, the dried sample may be eluted (for example by contacting the dried sample with water or an alcohol-water mixture such as a 10:90 vol/vol methanol/water mixture), dried (for example dried in oxygen-free environment such as a nitrogen environment), and reconstituted (for example reconstituted in water or in an aqueous solution). In certain embodiments, for example, at least a portion of the reconstituted sample may be provided to the singleplex or multiplex digital immunoassay. In certain embodiments, for example, at least a portion of the reconstituted sample may be centrifuged and supernatant (for example diluted or undiluted supernatant) provided to the singleplex or multiplex digital immunoassay.

In any of the embodiments disclosed herein, suitable collection paper may be collection paper sold under the trademark Schleicher & Schuell number 2992™ collection paper, collection paper sold under the trademark Schleicher & Schuell, 903™ collection paper, Whatman® protein saver card, or collection paper sold under the trademark Ahlströmer 226™ collection paper.

A schematic depiction of a method to form a liquid sample for assay from dried capillary blood obtained from a newborn infant is shown in FIG. 1. Droplets of capillary blood are obtained from a newborn infant and placed 100 on a card 102 in four filter paper collection portions of the card (including a first portion 104) and dried. The card 102 is stored 106 at 4° C. (or at ambient temperature) for a period of time during which small discs of the filter paper are removed from filter paper collection portions as needed for testing the blood contained thereon, leaving holes including a first hole 108. When a sample is desired, a hole punch is used to obtain 110 a 1-3 mM (or other convenient sized) disk 112 from the card, leaving behind a hole 114 in the card 102. The disk 112 is rehydrated and used to derive 116 the liquid sample 118 (in reaction vessel 120) containing first type of analyte molecule (for example a first analyte molecule 122) and a second type of analyte molecule (for example a second analyte molecule 124). For example, the first type of analyte molecule may be NF-L and the second type of analyte molecule may be GFAP. The liquid sample 118 is provided for assay 126 to quantify the concentration of at least one of the first type of analyte molecule and the second type of analyte molecule present in the liquid sample 118.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise contacting the dried sample with a solution containing assay microbeads (for example the contacting may occur in a reaction vessel). In certain embodiments, for example, the solution contacted with the dried sample may be incubated for a period of time (for example for at least 30 minutes, at least 1 hour, at least 2 hours, at least 6 hours, at least 12 hours, at least 24 hours, at least 48 hours, between 1 hour and 2 hours, between 1 hour and 6 hours, between 1 hour and 12 hours, or between 12 hours and 48 hours.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems for testing a liquid sample derived from a dried physiological sample (for example to detect neural injury). In certain embodiments, for example, the dried physiological sample may be at least 1 week old (for example the dried physiological sample may have been taken from a subject (for example by a heel prick or a finger prick) dried in air, and stored at a temperature of between −20° C. and 20° C. for at least one week) prior to deriving the liquid sample from the dried physiological sample, for example at least 2 weeks old, at least 1 month old, at least 2 months old, at least 3 months old, at least 6 months old, at least 12 months old, at least 2 years old, at least 3 years old, at least 4 years old, at least 5 years old, or the dried sample may be at least 10 years old prior to deriving the liquid sample from the dried physiological sample. In certain embodiments, for example, the dried physiological sample may be between 1 month and 20 years old prior to deriving the liquid sample, for example between 1 month and 6 years old, between 2 months and 3 years old, or the dried physiological sample may be between 3 years and 10 years old prior to deriving the liquid sample.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise obtaining or quantifying at least one parameter for at least one biomarker in the liquid sample. In certain embodiments, for example, the at least one biomarker may be a protein biomarker. In certain embodiments, for example, the at least one biomarker may be a phosphorylated protein biomarker. In certain embodiments, for example, the at least one biomarker may comprise a neurofilament. In certain embodiments, for example, the neurofilament may be a type IV intermediate filaments or heteropolymers. In certain embodiments, for example, the neurofilament may be selected from the group consisting of neurofilament heavy chain (NF-H), neurofilament medium chain (NF-M), NF-L, α-internexin, and peripherin. In certain embodiments, for example, the at least one biomarker may comprise NF-L. In certain embodiments, for example, the at least one biomarker may comprise GFAP. In certain embodiments, for example, the at least one biomarker may comprise UCH L1. In certain embodiments, for example, the at least one biomarker may comprise a tau protein (Tau), for example one isoform of tau protein, 2 isoforms of tau protein, 3 isoforms of tau protein, 4 isoforms of tau protein, 5 isoforms of tau protein, 6 isoforms of tau protein, or a phosphorylated tau protein (for example p-tau-81 or p-tau-231). In certain embodiments, for example, the tau protein may be tau 23. In certain embodiments, for example, the tau protein may be tau 24. In certain embodiments, for example, the tau protein may be tau 37. In certain embodiments, for example, the tau protein may be tau 34. In certain embodiments, for example, the tau protein may be tau 39. In certain embodiments, for example, the tau protein may be tau 40. In certain embodiments, for example, the tau protein may be phosphorylated. In certain embodiments, for example, the at least one biomarker may comprise a protein derived from amyloid beta precursor protein (for example a proteolytic product of amyloid beta precursor protein). In certain embodiments, for example, the at least one biomarker may comprise A beta 40. In certain embodiments, for example, the at least one biomarker may comprise A beta 42. In certain embodiments, for example, the at least one biomarker may comprise S100B. In certain embodiments, for example, the at least one biomarker may comprise NSE. In certain embodiments, for example, the at least one biomarker may comprise β-site aPP-cleaving enzyme 1 (BACe1). In certain embodiments, for example, the at least one biomarker may comprise myelin basic protein (MBP). In certain embodiments, for example, the at least one biomarker may comprise growth associated protein 43. In certain embodiments, for example, the at least one biomarker may comprise glutamine synthetase. In certain embodiments, for example, the at least one biomarker may comprise a glycine transporter (for example at least one of GLYT1 and GLYT2). In certain embodiments, for example, the at least one biomarker may comprise a neuron specific glycoprotein (for example GP50). In certain embodiments, for example, the at least one biomarker may comprise calpain. In certain embodiments, for example, the at least one biomarker may comprise heat shock protein 72. In certain embodiments, for example, the at least one biomarker may comprise a beta-amyloid precursor protein. In certain embodiments, for example, the at least one biomarker may comprise calbindin D-28K. In certain embodiments, for example, the at least one biomarker may comprise a proteolipid protein. In certain embodiments, for example, the at least one biomarker may comprise a myelin associated glycoprotein. In certain embodiments, for example, the at least one biomarker may comprise a creatine kinase protein (for example CK-BB). In certain embodiments, for example, the at least one biomarker may comprise an endothelium membrane protein (for example thrombomodulin).

In certain embodiments, for example, the at least one parameter may be determined from measurements for a selected number and combination of biomarkers associated with a neurological condition (for example a neural injury or a degenerative neurological disease). In certain embodiments, for example, the measurements may comprise concentrations of at least 2 biomarkers (for example 2 biomarkers, 3 biomarkers, 4 biomarkers, 5 biomarkers, 6 biomarkers, 7 biomarkers, 8 biomarkers, 9 biomarkers, 10 biomarkers, or more than 10 biomarkers). In certain embodiments, for example, the at least 2 biomarkers may be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise concentrations of at least 3 biomarkers. In certain embodiments, for example, the at least 3 biomarkers may be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise concentrations of at least 4 biomarkers. In certain embodiments, for example, the at least 4 biomarkers may be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise concentrations of at least 5 biomarkers. In certain embodiments, for example, the at least 5 biomarkers may be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise concentrations of at least 6 biomarkers. In certain embodiments, for example, the at least 2 biomarkers may be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise a concentration of NF-L and a concentration of at least one additional biomarker (for example concentrations of 2 additional biomarkers, 3 additional biomarkers, 4 additional biomarkers, 5 additional biomarkers, 6 additional biomarkers, 7 additional biomarkers, 8 additional biomarkers, 9 additional biomarkers, 10 additional biomarkers, or more than 10 additional biomarkers) selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the measurements may comprise concentrations of from 2 to 10 biomarkers, for example concentrations of from 2 to 8 biomarkers, from 2 to 5 biomarkers, or the measurements may comprise concentrations of from 2 to 4 biomarkers.

In certain embodiments, for example, the at least one biomarker indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or the at least one biomarker may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, the at least one biomarker may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, the at least one biomarker may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, the at least one biomarker may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, the at least one biomarker may be indicative of the neurological condition at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, the at least one biomarker may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, NF-L may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, GFAP may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, UCH L1 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, tau protein may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, A beta 40 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, A beta 42 may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, S100B may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of less than 1000 pg/mL, for example less than 100 pg/mL, less than 10 pg/mL, less than 1 pg/mL, less than 0.1 pg/mL, less than 0.01 pg/mL, or NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a molar concentration in the liquid sample of less than 0.001 pg/mL. In certain embodiments, for example, NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.001 pg/mL and 0.1 pg/mL. In certain embodiments, for example, NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 0.1 pg/mL and 10 pg/mL. In certain embodiments, for example, NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 1 pg/mL and 100 pg/mL. In certain embodiments, for example, NSE may be indicative of the neurological condition (for example a neural injury or a degenerative neurological disease) at a concentration in the liquid sample of between 10 pg/mL and 1000 pg/mL.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for tau protein.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for NF-L.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for GFAP.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for UCH-L1.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for A beta 40.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for A beta 42.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for S100B.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may require a LOQ of no greater than 0.01 pg/mL (for example no greater than 0.1 pg/mL, no greater than 0.5 pg/mL, no greater than 1 pg/mL, no greater than 2 pg/mL, no greater than 5 pg/mL, no greater than 10 pg/mL, or no greater than 50 pg/mL) for NSE.

In certain embodiments, for example, the at least one biomarker (or an elevated or reduced concentration of the at least one biomarker) may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or the at least one biomarker may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, the at least one biomarker may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or the at least one biomarker may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of NF-L may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of NF-L may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of NF-L may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of NF-L may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of GFAP may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of GFAP may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of GFAP may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of GFAP may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of UCH L1 may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of UCH L1 may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of UCH L1 may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of UCH L1 may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of tau protein may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of tau protein may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of tau protein may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of tau protein may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of A beta 40 may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of A beta 40 may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of A beta 40 may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of A beta 40 may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of A beta 42 may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of A beta 42 may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of A beta 42 may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of A beta 42 may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of S100B may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of S100B may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of S100B may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of S100B may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, an increased concentration of NSE may be indicative of a neural injury occurring during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of NSE may be indicative of a neural injury occurring during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject. In certain embodiments, for example, an increased concentration of NSE may be indicative of a neural injury being present during a time of between 1 second and 5 years prior to a date and time on which the physiological fluid was taken from a subject, for example during a time of between 1 second and 2 years, at time of between 1 second and 1 year, a time of between 1 second and 6 months, a time of between 1 second and 3 months, a time of between 1 second and 1 month, a time of between 1 second and 10 days, or an increased concentration of NSE may be indicative of a neural injury being present during a time of between 1 second and 1 days prior to a date and time on which the physiological fluid was taken from a subject.

In certain embodiments, for example, the at least one parameter may comprise a ratio of a concentration of a first biomarker to a concentration of a second component (for example a non-CNS protein or a second biomarker (for example a second biomarker comprising a CNS protein)) of the fluid sample. In certain embodiments, for example, the ratio may be indicative of the neurological condition at a value of at least 1% (for example at least 2%, at least 4%, at least 6%, at least 8%, at least 10%, at least 12%, at least 14%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%), at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, at least 100%, at least 110%, at least 115%, at least 120%, at least 140%, at least 150%, at least 200%, at least 250%, at least 300%, at least 350%, at least 400%, or between 1% and 400%, between 1% and 300%, between 1% and 200%, between 1% and 100%, between 1% and 50%, between 1% and 25%, between 1% and 10%, between 10% and 400%, between 10% and 300%, between 10% and 200%, between 10% and 100%, between 10% and 50%, between 50% and 400%, between 50% and 300%, between 50% and 200%, between 50% and 100%, between 50% and 75%, between 75% and 100%, or 1%, 2%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, 155%, 160%, 165%, 170%, 175%, 180%, 185%, 190%, 195%, 200%, 250%, 300%, 350%, or 400%. In certain embodiments, for example, the ratio may be indicative of the neurological condition at a value of between 1% and 500%, between 1% and 450%, between 1% and 400%, between 1% and 350%, between 1% and 300%, between 1% and 250%, between 1% and 200%, between 1% and 150%, between 1% and 100%, between 1% and 50%, between 1% and 25%, between 1% and 20%, between 1% and 15%, between 1% and 10%, between 1% and 5%, between 2% and 500%, between 2% and 450%, between 2% and 400%, between 2% and 350%, between 2% and 300%, between 2% and 250%, between 2% and 200%, between 2% and 150%, between 2% and 100%, between 2% and 50%, between 2% and 25%, between 2% and 20%, between 2% and 15%, between 2% and 10%, between 5% and 500%, between 5% and 450%, between 5% and 400%, between 5% and 350%, between 5% and 300%, between 5% and 250%, between 5% and 200%, between 5% and 150%, between 5% and 100%, between 5% and 50%, between 5% and 25%, between 5% and 20%, between 5% and 15%, between 5% and 10%, between 10% and 500%, between 10% and 450%, between 10% and 400%, between 10% and 350%, between 10% and 300%, between 10% and 250%, between 10% and 200%, between 10% and 150%, between 10% and 100%, between 10% and 50%, between 10% and 25%, between 10% and 20%, between 10% and 15%, between 15% and 500%, between 15% and 450%, between 15% and 400%, between 15% and 350%, between 15% and 300%, between 15% and 250%, between 15% and 200%, between 15% and 150%, between 15% and 100%, between 15% and 50%, between 15% and 25%, between 15% and 20%, between 20% and 500%, between 20% and 450%, between 20% and 400%, between 20% and 350%, between 20% and 300%, between 20% and 250%, between 20% and 200%, between 20% and 150%, between 20% and 100%, between 20% and 50%, between 20% and 25%, between 25% and 500%, between 25% and 450% between 25% and 400%, between 25% and 350%, between 25% and 300%, between 25% and 250%, between 25% and 200%, between 25% and 150%, between 25% and 100%, between 25% and 50%, between 50% and 500%, between 50% and 450%, between 50% and 400%, between 50% and 350%, between 50% and 300%, between 50% and 250%, between 50% and 200%, between 50% and 150%, between 50% and 100%, between 100% and 500%, between 100% and 450%, between 100% and 400%, between 100% and 350%, between 100% and 300%, between 100% and 250%, between 100% and 200%, between 100% and 150%, between 150% and 500%, between 150% and 450%, between 150% and 400%, between 150% and 350%, between 150% and 300%, between 150% and 250%, between 150% and 200%, between 200% and 500%, between 200% and 450%, between 200% and 400%, between 200% and 350%, between 200% and 300%, between 200% and 250%, between 250% and 500%, between 250% and 450%, between 250% and 400%, between 250% and 350%, between 250% and 300%, between 300% and 500%, between 300% and 450%, between 300% and 400%, between 300% and 350%, between 350% and 500%, between 350% and 450%, between 350% and 400%, between 400% and 500%, between 400% and 450%, or between 450% and 500%.

In certain embodiments, for example, the at least one parameter may comprise an increase (for example a percentage increase) in the concentration of a biomarker, for example a percentage increase of at least 1% (for example at least 2%, at least 4%, at least 6%, at least 8%, at least 10%, at least 12%, at least 14%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%), at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, at least 100%, at least 110%, at least 115%, at least 120%, at least 140%, at least 150%, at least 200%, at least 250%, at least 300%, at least 350%, at least 400%, or between 1% and 400%, between 1% and 300%, between 1% and 200%, between 1% and 100%, between 1% and 50%, between 1% and 25%, between 1% and 10%, between 10% and 400%, between 10% and 300%, between 10% and 200%, between 10% and 100%, between 10% and 50%, between 50% and 400%, between 50% and 300%, between 50% and 200%, between 50% and 100%, between 50% and 75%, between 75% and 100%, or 1%, 2%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, 155%, 160%, 165%, 170%, 175%, 180%, 185%, 190%, 195%, 200%, 250%, 300%, 350%, or 400%. In certain embodiments, for example, the at least one parameter may comprise a percentage increase in the concentration of a biomarker of between 1% and 500%, between 1% and 450%, between 1% and 400%, between 1% and 350%, between 1% and 300%, between 1% and 250%, between 1% and 200%, between 1% and 150%, between 1% and 100%, between 1% and 50%, between 1% and 25%, between 1% and 20%, between 1% and 15%, between 1% and 10%, between 1% and 5%, between 2% and 500%, between 2% and 450%, between 2% and 400%, between 2% and 350%, between 2% and 300%, between 2% and 250%, between 2% and 200%, between 2% and 150%, between 2% and 100%, between 2% and 50%, between 2% and 25%, between 2% and 20%, between 2% and 15%, between 2% and 10%, between 5% and 500%, between 5% and 450%, between 5% and 400%, between 5% and 350%, between 5% and 300%, between 5% and 250%, between 5% and 200%, between 5% and 150%, between 5% and 100%, between 5% and 50%, between 5% and 25%, between 5% and 20%, between 5% and 15%, between 5% and 10%, between 10% and 500%, between 10% and 450%, between 10% and 400%, between 10% and 350%, between 10% and 300%, between 10% and 250%, between 10% and 200%, between 10% and 150%, between 10% and 100%, between 10% and 50%, between 10% and 25%, between 10% and 20%, between 10% and 15%, between 15% and 500%, between 15% and 450%, between 15% and 400%, between 15% and 350%, between 15% and 300%, between 15% and 250%, between 15% and 200%, between 15% and 150%, between 15% and 100%, between 15% and 50%, between 15% and 25%, between 15% and 20%, between 20% and 500%, between 20% and 450%, between 20% and 400%, between 20% and 350%, between 20% and 300%, between 20% and 250%, between 20% and 200%, between 20% and 150%, between 20% and 100%, between 20% and 50%, between 20% and 25%, between 25% and 500%, between 25% and 450%, between 25% and 400%, between 25% and 350%, between 25% and 300%, between 25% and 250%, between 25% and 200%, between 25% and 150%, between 25% and 100%, between 25% and 50%, between 50% and 500%, between 50% and 450%, between 50% and 400%, between 50% and 350%, between 50% and 300%, between 50% and 250%, between 50% and 200%, between 50% and 150%, between 50% and 100%, between 100% and 500%, between 100% and 450%, between 100% and 400%, between 100% and 350%, between 100% and 300%, between 100% and 250%, between 100% and 200%, between 100% and 150%, between 150% and 500%, between 150% and 450%, between 150% and 400%, between 150% and 350%, between 150% and 300%, between 150% and 250%, between 150% and 200%, between 200% and 500%, between 200% and 450%, between 200% and 400%, between 200% and 350%, between 200% and 300%, between 200% and 250%, between 250% and 500%, between 250% and 450%, between 250% and 400%, between 250% and 350%, between 250% and 300%, between 300% and 500%, between 300% and 450%, between 300% and 400%, between 300% and 350%, between 350% and 500%, between 350% and 450%, between 350% and 400%, between 400% and 500%, between 400% and 450%, or between 450% and 500%, for example as compared to a reference level.

In certain embodiments, for example, the at least one parameter may comprise a reduction (for example a percentage reduction) in the concentration of a biomarker of between 1% and 99%, for example between 1% and 95%, between 1% and 90%, between 1% and 85%, between 1% and 80%, between 1% and 75%, between 1% and 70%, between 1% and 65%, between 1% and 60%, between 1% and 55%, between 1% and 50%, between 1% and 45%, between 1% and 40%, between 1% and 35%, between 1% and 30%, between 1% and 25%, between 1% and 20%, between 1% and 15%, between 1% and 10%, between 1% and 5%, between 5% and 99%, between 5% and 95%, between 5% and 90%, between 5% and 85%, between 5% and 80%, between 5% and 75%, between 5% and 70%, between 5% and 65%, between 5% and 60%, between 5% and 55%, between 5% and 50%, between 5% and 45%, between 5% and 40%, between 5% and 35%, between 5% and 30%, between 5% and 25%, between 5% and 20%, between 5% and 15%, between 5% and 10%, between 10% and 99%, between 10% and 95%, between 10% and 90%, between 10% and 85%, between 10% and 80%, between 10% and 75%, between 10% and 70%, between 10% and 65%, between 10% and 60%, between 10% and 55%, between 10% and 50%, between 10% and 45%, between 10% and 40%, between 10% and 35%, between 10% and 30%, between 10% and 25%, between 10% and 20%, between 10% and 15%, between 15% and 99%, between 15% and 95%, between 15% and 90%, between 15% and 85%, between 15% and 80%, between 15% and 75%, between 15% and 70%, between 15% and 65%, between 15% and 60%, between 15% and 55%, between 15% and 50%, between 15% and 45%, between 15% and 40%, between 15% and 35%, between 15% and 30%, between 15% and 25%, between 15% and 20%, between 20% and 99%, between 20% and 95%, between 20% and 90%, between 20% and 85%, between 20% and 80%, between 20% and 75%, between 20% and 70%, between 20% and 65%, between 20% and 60%, between 20% and 55%, between 20% and 50%, between 20% and 45%, between 20% and 40%, between 20% and 35%, between 20%) and 30%, between 20% and 25%, between 25% and 99%, between 25% and 95%, between 25% and 90%, between 25% and 85%, between 25% and 80%, between 25% and 75%, between 25% and 70%, between 25% and 65%, between 25% and 60%, between 25% and 55%, between 25% and 50%, between 25% and 45%, between 25% and 40%, between 25% and 35%, between 25% and 30%, between 30% and 99%, between 30% and 95%, between 30% and 90%, between 30% and 85%, between 30% and 80%, between 30% and 75%, between 30% and 70%, between 30% and 65%, between 30% and 60%, between 30% and 55%, between 30% and 50%, between 30% and 45%, between 30% and 40%, between 30% and 35%, between 35% and 99%, between 35% and 95%, between 35% and 90%, between 35% and 85%, between 35% and 80%, between 35% and 75%, between 35% and 70%, between 35% and 65%, between 35% and 60%, between 35% and 55%, between 35% and 50%, between 35% and 45%, between 35% and 40%, between 40% and 99%, between 40% and 95%, between 40% and 90%, between 40% and 85%, between 40% and 80%, between 40% and 75%, between 40% and 70%, between 40% and 65%, between 40% and 60%, between 40% and 55%, between 40% and 50%, between 40% and 45%, between 45% and 99%, between 45% and 95%, between 45% and 90%, between 45% and 85%, between 45% and 80%, between 45% and 75%, between 45% and 70%, between 45% and 65%, between 45% and 60%, between 45% and 55%, between 45% and 50%, between 50% and 99%, between 50% and 95%, between 50% and 90%, between 50% and 85%, between 50% and 80%, between 50% and 75%, between 50% and 70%, between 50% and 65%, between 50% and 60%, between 50% and 55%, between 55% and 99%, between 55% and 95%, between 55% and 90%, between 55% and 85%, between 55% and 80%, between 55% and 75%, between 55% and 70%, between 55% and 65%, between 55% and 60%, between 60% and 99%, between 60% and 95%, between 60% and 90%, between 60% and 85%, between 60% and 80%, between 60% and 75%, between 60% and 70%, between 60% and 65%, between 65% and 99%, between 65% and 95%, between 65% and 90%, between 65% and 85%, between 65% and 80%, between 65% and 75%, between 65% and 70%, between 70% and 99%, between 70% and 95%, between 70% and 90%, between 70% and 85%, between 70% and 80%, between 70% and 75%, between 75% and 99%, between 75% and 95%, between 75% and 90%, between 75% and 85%, between 75% and 80%, between 80% and 99%, between 80% and 95%, between 80% and 90%, between 80% and 85%, between 85% and 99%, between 85% and 95%, between 85% and 90%, between 90% and 99%, between 90% and 95%, or between 95% and 99%.

A schematic depiction of a method to quantify the concentration of a biomarker from a liquid sample is shown in FIG. 2. Capture objects including a first capture object 202 having an anti-analyte immobilization agent 204 are combined 200 with the liquid sample 118, wherein the anti-analyte immobilization agent 204 is specific to the first type of analyte molecule. The added capture objects are incubated 206 with the liquid sample 118 for a period of time, resulting in the first capture object 202 binding with the first analyte molecule 122. As shown, some of the capture objects do not bind with any analyte, and the capture objects are not selective to and do not bind to any of the second type of analyte (for example to second analyte molecule 124). An excess number of capture objects is provided whereby the fraction of capture objects binding with more than one analyte is statistically insignificant. Following incubation and binding between analyte molecules and capture objects, detectable agents configured to bind with the first type of analyte (for example a detectable agent 210) are contacted 208 with the capture objects and incubated 212, resulting in the detectable agent 210 binding to the first analyte molecule 122. As shown, detectable agents will not bind to a capture object unless the capture object has immobilized an analyte molecule. Following addition of detectable agents, the capture objects are spatially separated 214 into a plurality of reaction vessels (for example femtoliter-sized reaction vessels) on a substrate 216. As shown, the first capture object 202 along with additional capture objects are present in separate reaction vessels while two of the reaction vessels (for example a reaction vessel 218) do not retain any capture objects. The substrate 216 may then be analyzed 220 by an optical-based analyzer 222 to determine the number of reaction vessels containing an analyte bound to a capture object, wherein in the number may be related to a measure of the concentration of analyte in the liquid sample 118.

A schematic depiction of a method to quantify the concentration of a biomarker from a liquid sample is shown in FIG. 3. Capture objects including a first capture object 202 having a first anti-analyte immobilization agent 204 and a second capture object 302 having a second anti-analyte immobilization agent 304 are combined 300 with the liquid sample 118, wherein the first anti-analyte immobilization agent 204 is specific to the first type of analyte molecule and the second anti-analyte immobilization agent 304 is specific to the second type of analyte molecule. The added capture objects are incubated 306 with the liquid sample 118 for a period of time, resulting in the first capture object 202 binding with the first analyte molecule 122 and the second capture object 302 binding with the second analyte molecule 124. As shown, some of the capture objects do not bind with any analyte. An excess number of capture objects is provided whereby the fraction of capture objects binding with more than one analyte is statistically insignificant. After the capture objects have immobilized at least a portion of the analyte molecules, a first type of detectable agent (for example a first detectable agent 310) configured to bind with the first type of analyte and second type of detectable agent (for example a second detectable agent 312) configured to bind with the second type of analyte are contacted 308 with the capture objects and incubated 314, resulting in the first detectable agent 310 binding to the first analyte molecule 122 and the second detectable agent 312 binding to the second analyte molecule 124. As shown, detectable agents do not bind to a capture object unless the capture object has immobilized an analyte molecule. The capture objects are spatially separated 316 into a plurality of reaction vessels (for example femtoliter-sized reaction vessels etched in a plate) on a substrate 216. As shown, the first capture object 202 along with additional capture objects are present in separate reaction vessels. The substrate 216 may then be analyzed 318 by an optical-based analyzer 222 to determine the number of reaction vessels containing an analyte bound to a capture object, wherein in the number of the first type of analyte molecule and the number of the second type of analyte molecule may be related to a measures of the concentration of each type of analyte in the liquid sample 118.

A schematic depiction of a method to quantify concentrations of one or more analytes (for example one or more analytes selected from the group consisting of NF-L, GFAP, UCH L1 Tau, A beta 40, A beta 42, S100B and NSE) in a liquid sample (for example a liquid sample derived from a dried blood spot sample) via a multi-spotted reaction well (for example one well of a plurality of such wells) is shown in FIG. 12. The liquid sample 118 (in vessel 120) is provided 116 containing one or more types of analyte molecules, for example a first type of analyte molecule (for example a first analyte molecule 122), a second type of analyte molecule (for example a second analyte molecule 128), a third type of analyte molecule (for example a third analyte molecule 124), and a fourth type of analyte molecule (for example a fourth analyte molecule 130). For example, the one or more kinds of analytes can be selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B and NSE. One or more anti-analyte immobilization agents, for example a first type of anti-analyte immobilization agent (for example the anti-analyte immobilization agent 1200), a second type of anti-analyte immobilization agent (for example the anti-analyte immobilization agent 1202), a third type of anti-analyte immobilization agent (for example the anti-analyte immobilization agent 1204), and a fourth type of anti-analyte immobilization agent (for example the anti-analyte immobilization agent 1206), are immobilized in a plurality of spatially separated zones (or “spots”) in a reaction well 1208. For example, a first spot 1210 contains a plurality of the first type of anti-analyte immobilization agent exclusive of the other types of anti-analyte immobilization agents; a second spot 1212 contains a plurality of the second type of anti-analyte immobilization agent exclusive of the other types of anti-analyte immobilization agents; a third spot 1214 contains a plurality of the third type of anti-analyte immobilization agent exclusive of the other types of anti-analyte immobilization agents; and a fourth spot 1216 contains a plurality of the fourth type of anti-analyte immobilization agent exclusive of the other types of anti-analyte immobilization agents. The liquid sample 118 is added 1218 to the reaction well 1208, wherein the one or more anti-analyte immobilization agents are each specific to a type of analyte molecules, for example the first anti-analyte immobilization agent 1200 is specific to the first type of analyte molecule, the second anti-analyte immobilization agent 1202 is specific to the second type of analyte molecule, the third anti-analyte immobilization agent 1204 is specific to the third type of analyte molecule, and the fourth anti-analyte immobilization agent 1206 is specific to the fourth type of analyte molecule. The one or more anti-analyte immobilization agents are incubated 1220 with the liquid sample 118 for a period of time, resulting in the one or more anti-analyte immobilization agent each binding with the corresponding type of analyte molecule (for example the first anti-analyte immobilization agent 1200 binding with the first analyte molecule 122, the second anti-analyte immobilization agent 1202 binding with the second analyte molecule 128, the third anti-analyte immobilization agent 1204 binding with the third analyte molecule 124, and the fourth anti-analyte immobilization agent 1206 binding with the fourth analyte molecule 130). In certain embodiments, for example, the reaction well may be agitated according to a predetermined scheme to increase fluid flow of the liquid sample relative to the one or more spatially separated zones and thereby achieve one or more of increased sensitivity (for example lower LOQ), reduced assay time, and assay reproducibility. After the anti-analyte immobilization agents have immobilized at least a portion of the analyte molecules (not all analyte molecules are shown), one or more types of detectable agents each configured to bind with a type of analyte (for example a first type of detectable agent (for example a first detectable agent 1222) configured to bind with the first type of analyte, a second type of detectable agent (for example a second detectable agent 1224) configured to bind with the second type of analyte, a third type of detectable agent (for example a third detectable agent 1226) configured to bind with the third type of analyte, and a fourth type of detectable agent (for example a fourth detectable agent 1228) configured to bind with the fourth type of analyte), are contacted 1230 with the plurality of spatially separated zones and incubated 1232 in the reaction well 1208, resulting in one or more types of detectable agents each binding to the corresponding type of analyte molecule (for example the first detectable agent 1222 binding to the first analyte molecule 122, the second detectable agent 1224 binding to the second analyte molecule 128, the third detectable agent 1226 binding to the third analyte molecule 124, and the fourth detectable agent 1228 binding to the fourth analyte molecule 130). Detectable agents do not bind to an anti-analyte immobilization agent unless the anti-analyte immobilization agent has immobilized an analyte molecule (not all detectable agents molecules are shown). The substrate 1234 may then be analyzed 1236 by an optical-based analyzer 1238 to determine the signal levels in spatially separated reaction vessels containing an analyte bound to an anti-analyte immobilization agent, wherein in the signal levels of one or more analyte molecules (for example one or more analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B and NSE), for example the signal level of the first type of analyte molecule, the signal level of the second type of analyte molecule, the signal level of the third type of analyte molecule, and the signal level of the fourth type of analyte molecule may be related to a measures of the concentration of each type of analyte in the liquid sample 118. For example, the signal may comprise a chemilluminecent signal. In certain embodiments, for example, NF-L quantification via the described detection of analytes in the spotted reaction well may provide one or more of the same level of sensitivity, LOQ, and LOD as one or more of the digital assays described herein or in one of the INCORPORATED REFERENCES.

Any of the disclosed methods, tests, protocol, assays, kits, or systems may comprising processing the results of one or more assays (for example the concentrations of one or more biomarkers) into useful information regarding a risk, diagnosis, prognosis, or state of a neurological condition (for example a neural injury or a degenerative neurological disease) in a subject (for example a human subject such as a neonate) by passing the results through a classification model to compute at least one classification value which can be compared to at least one threshold value.

In certain embodiments, for example, the at least one threshold value may correspond to a predetermined sensitivity level for a multivariate statistical model of the expression levels of one or more biomarkers in a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of training samples from individuals diagnosed as having an indicated neurological condition (for example a neural injury such as a traumatic brain injury or a degenerative neurological disease) and control samples from individuals without the indicated neurological condition (for example a neural injury such as a traumatic brain injury or a degenerative neurological disease). In certain embodiments, for example, the subject's classification value may be calculated using the multivariate statistical model. In certain embodiments, for example, the multivariate statistical model may comprise a binary logistic regression, a linear regression, a quadratic regression, a polynomial regression, a logistic regression, results of a principal component analysis, results of a maximum likelihood analysis, a neural network, results of a linear discriminant analysis, a decision tree, or a combination of two or more of the foregoing.

Certain embodiments, for example, may provide methods, tests, assays, kits, or systems to measure at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE may be detected by a multiplex assay. In certain embodiments, for example, the multiplex assay may comprise adding portions of a liquid sample (for example a liquid sample derived from a dried sample of human physiological fluid such as human blood serum or plasma) to a plurality of reaction wells (for example a 96-well assay plate). In certain embodiments, for example, each of the reaction wells may comprise a plurality of zones (or spots). In certain embodiments, for example, the plurality of zones (or spots) may be spatially separated. In certain embodiments, for example, the zones by be radially disposed (for example symmetrically disposed at a fixed radius about a central position in each reaction well). In certain embodiments, for example, each of the reaction wells may be sized to contain, in total, between 20 mcL and 100 mcL (for example 50 mcL) of liquid sample and assay reagents. In certain embodiments, for example, each of the zones may be coated (or covalently conjugated to) a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of an anti-analyte agent that is specific to one of at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, whereby, for example, a first zone of each reaction well will preferentially immobilize NF-L, a second zone of each reaction well will preferentially immobilize GFAP, a third zone of each reaction well will preferentially immobilize UCH L1, a fourth zone of each reaction well will preferentially immobilize Tau, and further zones of each reaction well will preferentially immobilize one or more of A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the multi-well plate may be coupled to a digital nanofluidic deposition system for controlled addition of sample, washing reagents, and detection agents. In certain embodiments, for example, detectable agents (for example four different detectable agents having different colors or the same color) may be added to each of the reaction wells to bind with immobilized biomarkers and produce a detectable signal. In certain embodiments, for example, the multi-well plate may made of translucent plastic. In certain embodiments, for example, imaging of detectable signals may be performed through the bottom of the translucent multi-well plate. In certain embodiments, for example, the multi-well plate may be coupled to an agitation system. In certain embodiments, for example, the agitation system may be configured to agitate the multi-well plate to form a vortex of fluid in each reaction well.

In certain embodiments, for example, the multiplex assay may comprise agitating the liquid sample, for example agitating the liquid sample for up to 1 hour, up to 1.5 hours, up to 2 hours, up to 2.5 hours, up to 3 hours, up to 3.5 hours, up to 4 hours, up to 4.5 hours, up to 5 hours, up to 6 hours, up to 8 hours, up to 10 hours, up to between 1 hour and 3 hours, up to between 1.5 hours and 2.5 hours, for 2 hours, or for greater than 10 hours. In certain embodiments, for example the multiplex assay may comprise adding biotinylated detection antibodies, followed by an additional 30 minutes of shaking. In certain embodiments, for example, the detection antibodies may bind to form an amino complex. In certain embodiments, for example, horseradish peroxidase (HRP)-conjugated streptavidin may be added, followed by an additional 30 minute agitation cycle, substrate added, and the zones containing at least two biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE detected via chemiluminescent signal. In certain embodiments, for example, a machine learning algorithm may optimize exposure times in the number of images for each sample to maximize sensitivity and dynamic range. In certain embodiments, for example, the multiplex assay may be performed within 6 hours inclusive of preparation of a the liquid sample from a dried sample of physiological fluid, for example within 5 hours, within 4 hours, within 3 hours within 2 hours, within 1 hour, within 30 minutes, within between 1 hour and 6 hours, within between 2 hours and 4 hours, within between 2.5 hours and 3.5 hours, or within 3 hours.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems for determining a measure of the concentration of a panel of neurological biomarkers in a sample derived from a human (for example a dried capillary blood sample obtained by a heel prick or a finger prick from a human patient such as a newly born infant) are disclosed. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may involve determining the concentration of two or more biomarkers associated with brain injury and/or neurodegeneration in a human sample. In certain embodiments, for example, the method may comprise determining a measure of the concentration of NF-L and at least one other biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. An exemplary method and kit may be directed to determination of a measure of the concentration of a biomarker panel comprising at least NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, a measure of the concentration of the biomarkers may be determined using a single assay. In some such cases, the assay may utilize certain assay conditions that allow for the determination of each biomarker with a relatively high specificity and sensitivity. The methods, tests, protocol, assays, kits, and systems described herein may be used to assess a variety of brain injuries and neurodegenerative conditions, including traumatic brain injury.

A cascade of biomarkers, such as NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSEs, may be generated in the brain in response to and/or in proportion to the extent of a brain injury. NF-L, a cytoskeletal intermediate filament protein, may combine with other proteins to form neurofilaments in neurons and may be released in significant quantity following axonal damage or neuronal degeneration. Tau protein, a microtubule-stabilizing protein primarily localized in CNS neurons, may be observed in the CSF of patients with neurodegenerative disease and head injuries, suggesting its extracellular release during neuronal damage and a role as a biomarker with specificity for brain injury. GFAP, a class-III intermediate filament involved in many CNS processes including cell communication and the functioning of the blood brain barrier, may be associated with multiple diseases such as traumatic brain injury, stroke, brain tumors, etc. UCH-L1, which hydrolyzes small C-terminal adducts of ubiquitin to generate the ubiquitin monomer and is expressed predominantly in neurons, may be released from injured neurons and flow into the CSF and circulating blood. Such biomarkers could in turn diffuse across the blood brain barrier and into the blood in response to and/or in proportion to the extent of the injury, and may be generally found in low abundance. In certain embodiments, for example, the ability to determine a measure of the concentration of two or more biomarkers (for example three or more biomarkers, four or more biomarkers) in a patient sample (or a plurality samples) obtained following a suspected injury event may be used to determine whether brain injury occurred and/or otherwise assess the injury. For example, a measure of the concentration of two or more biomarkers may be used to assess the severity of the brain injury.

In certain embodiments, for example, sample(s) of the patient's CSF may be obtained and analyzed to determine a measure of the concentration of the biomarkers. In certain embodiments, for example, it may be advantageous to determine the level of biomarkers in the blood of a patient as compared to CSF, as blood sampling may be generally less invasive and may result in fewer complications as compared to CSF sampling. However, many of the biomarkers that are present in the CSF have a slow rate of transmission across and/or a high barrier of transportation across the blood-brain barrier (BBB) and thus, a measure of the concentration of the biomarkers in the patient's blood is generally sufficiently lower as compared to a measure of the concentration in CSF, which can make it difficult or impossible to accurately determine using typically employed conventional immunoassays. Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems that have very low limits of quantification (LOQ) and/or limits of detection (LOD) can facilitate determination of a measure of the concentration of such biomarkers in the patient's blood with sufficient accuracy and repeatability to provide statistically significant and/or meaningful results. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may have very low LODs and/or LOQs (for example in the low pg/mL range) to determine a measure of the concentration of two or more biomarkers in a sample obtained from a patient following a suspected injury event. In certain embodiments, for example, one or more parameters related to the concentrations of the biomarkers in the sample (for example blood sample) may be correlated with the diagnosis of brain injury, the assessment of the extent of brain injury, and/or a method of treatment following the injury event.

It should be noted, that while many of the embodiments described herein focus on brain injuries caused by traumatic events, this is by no way limiting, and In certain embodiments, for example, the brain injury may be caused by other events, for example, a biochemical event, such as oxygen deprivation (hypoxia). Hypoxia generally refers to a deficiency in the amount of oxygen reaching body tissues or a condition of insufficient levels of oxygen in issue or blood. Oxygen deprivation to the brain results in neuronal damage and death, which is in turn related to the extent of long term brain dysfunction.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of two or more biomarkers selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, NSE, and NF-L. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L protein and at least one other biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and GFAP. In certain embodiments, for example, the method may comprise determining a measure of the concentration of NF-L and UCH-L1. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and Tau protein. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and A beta 40. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and A beta 42. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of NF-L and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and at least one other biomarker selected from the group consisting of UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and UCH-L1. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and Tau. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and A beta 40. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and A beta 42. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of GFAP and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and at least one other biomarker selected from the group consisting of Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and Tau. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and A beta 40. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and A beta 42. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of UCH-L1 and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of Tau and at least one other biomarker selected from the group consisting of A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of Tau and A beta 40. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of Tau and A beta 42. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of Tau and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of Tau and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 40 and at least one other biomarker selected from the group consisting of A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 40 and A beta 42. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 40 and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 40 and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 42 and at least one other biomarker selected from the group consisting of S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 42 and S100B. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of A beta 42 and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of S100B and NSE.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise measuring a selected number and combination of biomarkers associated with brain injury and/or neurodegeneration. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining the concentration of two biomarkers. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining the concentration of three biomarkers. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of at least the following four biomarkers: Tau, GFAP, UCH-L1, and NF-L. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining the concentration of at least about 1 biomarker, at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, or at least about 10 biomarkers. In certain embodiments, for example, the number of biomarkers, whose concentration may be determined, may range from 2 to 10, from 2 to 8, ranges from 2 to 6, or from 2 to 5 (for example from 2 to 4).

In certain embodiments, for example, an immunoassay may be used to determine a measure of the concentration of two or more biomarkers. In certain embodiments, for example, the immunoassay may be a multiplex assay in which the concentration of more than one biomarker is measured in a single performance of the assay. In such cases, at least some (for example all) of the biomarkers may be measured at one time. Certain embodiments may provide, for example, systems and methods that allow for the selective and sensitive detection and quantification of biomarkers (for example in a multiplex assay).

In many conventional assay systems, multiplexing is hindered by non-specific binding, cross-reactivity (for example between detection molecules for a first biomarker and a second biomarker), the relative concentrations of the biomarkers, and/or incompatibility between the assay conditions (for example dilution, detection molecules, pH, solvent, reagents) for a first biomarker and the assay conditions for a second biomarker. For instance, certain conventional reagents necessary for ultrasensitive detection of a first analyte (for example Tau) may not allow for accurate detection of a second analytes (for example UCH-L1). For example, certain conventional detergents while beneficial for the detection of Tau may induce conformational changes (for example due to physicochemical alterations in solvation activity) in other analytes (for example biomarkers), such as UCH-L1, that adversely affect presentation of the portion (for example antigenic epitope) of the analyte utilized for detection. For instance, a conventional detergent may cause the antigenic epitope of an analyte to be less available or overly available for binding to a detection molecule (for example antibody) resulting in inaccurate quantification and/or a relatively high LOQ and/or LOD. As another example, certain detection molecules utilized for ultrasensitive detection of a biomarker may cross-react or non-specifically bind with another biomarker or detection molecule resulting in inaccurate quantification of the biomarker. For instance, detection molecules for certain biomarkers (for example NF-L, GFAP, and/or Tau) may cross-react or non-specifically bind with UCH-L1 resulting in inaccurate quantification of the biomarker(s). As yet another example, molecules used to calibrate the multiplex assay may non-specifically bind resulting in inaccurate quantification. For instance, a biomarker standard (for example GFAP standard) used for calibration of the biomarker may non-specifically bind to assay components (for example molecules, beads) necessary for the detection (for example quantification) of other biomarkers.

In certain embodiments, for example, the concentration of detection molecules that affords relatively low LODs and LOQs in a non-multiplex assay may result in cross-reactivity or non-specific binding in a multiplex assay. In certain embodiments, for example, a high sensitivity assay may be provided which requires relatively low background levels, such that signal-to-noise may be adequate at low analyte (for example biomarker) concentrations to permit reliable measurement. Non-specific binding between assay components for a biomarker and assay components for another biomarker increases background levels resulting in a reduced signal-to-noise ratio and accordingly reduced sensitivity. In certain embodiments, for example, certain conventional diluents that produce acceptable dilution linearity and spike recovery for the detection of a biomarker may result in dilution non-linearity and/or unpredictable spike recovery for another biomarker. In many assays, one or more blocker reagents may be included in a sample diluent to mimic the physicochemical properties of the native sample in order to allow for acceptable dilution linearity. Diluents, and accordingly the blocker reagents comprised therein, that do not result in linear dilution may be unsuitable for use in the assay. In multiplex assays, suitable diluents should produce acceptable dilution linearity for each analyte (for example biomarkers). Many conventional diluents generally employed may be unsuitable for multiplexing. The problems associated with multiplexing often amplify as the number of biomarkers to be multiplexed increases. Thus, for many conventional assay systems, multiplexing of certain biomarkers is difficult and/or not possible.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems that do not suffer from one or more limitations of conventional immunoassays with respect to multiplexing biomarkers, and thus can provide an improved way to measure biomarkers associated with brain injury and/or neurodegeneration. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems provide ultra-sensitive detection of two or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise certain assay conditions (for example detection molecules, blockers, detergents, concentrations) that allow for sub-femtomolar detection of at least some (for example each) of the biomarkers.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize one or more reagents and/or techniques that reduce and/or eliminate cross-reactivity, non-specific binding, dilution non-linearity, unpredictable spike recovery, and/or adverse analyte (for example protein) confirmation. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize a detergent that promotes favorable biomarker confirmation for at least some (for example two or more, three or more, all) of the biomarkers in the multiplex assay. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize a detergent that promotes a confirmation of NF-L and another biomarker (for example UCH-L1, GFAP, and/or Tau) that is favorable for accurate detection (for example quantification). In certain embodiments, for example, use of the detergents described herein may allow for the detection of multiple biomarkers in a single assay that may not be measured using conventional detergents generally employed. In certain embodiments, for example, use of the detergents described herein may allow for the detection of both Tau and UCH-LI in the multiplexed assay. Conversely, some conventional detergents that allow for the detection of tau proteins cause UCH-L1 to be undetectable. Non-limiting examples of suitable detergents include non-ionic detergents, such as Triton™ X-100, the non-ionic surfactant sold under the trademark Triton™ X-114, Tween-20, Tween-80, and combinations thereof.

In certain embodiments, for example, the detergent may be used during one or more assay steps and/or present in one or more assay compositions (for example diluent composition). In certain embodiments, for example, the detergent may be present during the detection step. In certain embodiments, for example, the detergent may be present in the diluent composition. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize a diluent comprising a detergent (for example Triton X-100, Triton X-114) at a concentration of between about 0.1 wt. % and about 1.0 w.t% (for example about 0.5 wt. %). In certain embodiments, for example, the presence of the detergent in the diluent composition may allow for the accurate detection (for example quantification) of the biomarkers in the multiplex assay and/or a relatively low LOD and/or LOQ. In certain embodiments, for example, the absence of a detergent in one or more assay steps and/or assay compositions may result in one or more biomarkers (for example UCH-L1) being undetectable.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize one or more reagents that reduce and/or eliminate cross-reactivity or non-specific binding between assay components (for example detection molecules, calibration molecules, biomarker) for one biomarker and assay components for another biomarker. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize detection and/or calibration molecules that have relatively low non-specific binding and/or cross-reactivity with other components in the multiplex assay. In certain embodiments, for example, use of the detection and/or calibration molecules described herein allowed for the detection of multiple biomarkers in a single assay that could not be accurately measured, measured with acceptable clinical discrimination, and/or measured with low LOQ and/or LOD using certain conventional detection and/or calibration molecules. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize certain combinations of UCH-L1 clones (for example human recombinant protein, UCH-L1 clones 10D1 and 1033) that provide relatively high clinical discrimination, relatively low non-specific binding, and relatively low cross-reactivity with other assay components (for example other biomarkers). Conversely, conventional combinations of UCH-L1 clones that provide relatively low LOD for UCH-L1 may produce poor clinical discrimination for other biomarkers, have high non-specific binding with assay components for other biomarkers, or otherwise adversely affect the detection of other biomarkers in the multiplex assay. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize certain GFAP standards (for example Hytest native human GFAP) for calibration that do not cross-react and/or non-specifically bind with the assay components for the NF-L, UCH-L1, and/or Tau assays, whereby the cross-reactivity between the GFAP calibration standard that results in a non-specific signal in non-GFAP assays (for example NF-L, UCH-L1, and/or Tau assays) with increasing doses of GFAP antigen may be reduced and/or eliminated.

In certain embodiments, for example, the concentration of one or more binding ligands used in the multiplex assay may be less than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the binding ligand may be a molecule, particle, or the like which specifically binds to or otherwise specifically associates with a biomarker molecule to aid in the detection of the biomarker molecule. In certain embodiments, for example, the binding ligand may comprise an antibody for the biomarker that may be directly or indirectly detected. Other embodiments are contemplated herein. In certain embodiments, for example, the concentration of one or more binding ligands used in the multiplex assay may range from about 2 to about 10 (for example from about 2 to about 8, from about 4 to about 10, from about 4 to about 8) times less than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the concentration of binding ligands used in a single biomarker assay may result in cross-reactivity and/or non-specific binding with assay components for another assay. In certain embodiments, for example, the UCH-L1 binding ligand (for example clone 1033) concentrations for a single biomarker assay may result in a relatively high amount of non-specific binding. In certain embodiments, for example, the concentration of the UCH-L1 binding ligand in the multiplex assay may be at least about 2 times (for example at least about 4 times, about 6 times) less than the concentration utilized in the single biomarker assay. In certain embodiments, for example, the concentration of one or more binding ligands in the multiplex assay may be in the range of from about 0.1 to about 2 μg/mL, whereby cross reactivity and/or non-specific binding is reduced or eliminated.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize one or more reagents and/or techniques that reduce and/or eliminate dilution non-linearity and unpredictable spike recovery for each biomarker (for example NF-L, GFAP, UCH-L1, and/or Tau). In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize one or more blockers that promote dilution linearity (for example of a tested sample when diluted with a sample diluent) and predictable spike recovery. In certain embodiments, for example, the one or more blockers may serve to reduce and/or eliminate sample matrix effects that adversely affect linearity, spike recovery, and/or quantification. In certain embodiments, for example, the term “blocker” may refer to a reagent (for example protein-containing reagent) designed to competitively block non-specific binding. In certain embodiments, for example, the blocker may comprise one or more proteins. In certain embodiments, for example, the blocker reagent may contain multiple proteins (for example IgG), to block non-specific interactions between monoclonal antibodies (for example mouse monoclonal antibodies). In certain embodiments, for example, the blocker reagents may comprise proteins or antibodies from different animal species (for example mouse, bovine, human). Non-limiting examples of suitable blockers include globulin (for example bovine gamma globulin), albumin (for example bovine serum albumin), TRU block®, Superchemiblock®, and combinations thereof. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may utilize (for example in a diluent) two or more blockers (for example three or more, four). In certain embodiments, for example, a diluent may comprise a globulin (for example bovine gamma globulin, in the range of about 0.005 wt. % to about 0.2 wt. %,) an albumin (for example bovine serum albumin, in the range of about 0.01 wt. % to about 0.1%), TRUblock (for example in the range of about 5 μg/mL to about 20 μg/mL), and/or Superchemiblock (for example in the range of about 10 μg/mL to about 100 μg/mL, in the range of about 10 μg/mL to about 100 μg/mL). In certain embodiments, for example, the diluent may comprise a carbohydrate (for example dextrose, in a range of about 0.005 wt. % to about 0.05 wt. %), a nitrogen containing small molecule (for example urea, in a range of about 1 mM to about 10 mM), and/or a detergent (for example Triton X100, in a range of about 0.2 wt. % to about 1 wt. %).

In certain embodiments, for example, the concentration of one or more blockers used in the multiplex assay may be greater than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the concentration of one or more blockers and/or all blockers used in the multiplex assay may range from about 5 to about 100 times (for example from about 10 to about 100, from about 20 to about 100, from about 5 to about 50) greater than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the concentration of one or more blockers (for example TRU™ block, Superchemiblock™) and/or all blockers in an assay composition (for example diluent, detection composition) may be at least about 10 μg/mL, at least about 15 μg/mL, at least about 20 μg/mL, at least about 30 μg/mL, at least about 40 μg/mL, at least about 50 μg/mL, at least about 60 μg/mL, at least about 70 μg/mL, at least about 80 μg/mL, at least about 90 μg/mL, at least about 100 μg/mL, at least about 125 μg/mL, at least about 150 μg/mL, at least about 175 μg/mL, or at least about 200 μg/mL. In certain embodiments, for example, the concentration of one or more blockers (for example TRU™ block, Superchemiblock™) and/or all blockers in an assay composition may ranges from about 10 μg/mL to about 200 μg/mL (for example 10 μg/mL to about 100 μg/mL, 5 μg/mL to about 20 μg/mL, 50 μg/mL to about 100 μg/mL).

In certain embodiments, for example, the concentration of one or more blockers used in the multiplex assay may be greater than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the concentration of one or more blockers and/or all blockers used in the multiplex assay may range from about 5 to about 100 times (for example from about 10 to about 100, from about 20 to about 100, from about 5 to about 50) greater than the concentration utilized in a single biomarker assay. In certain embodiments, for example, the concentration of one or more blockers (for example TRUblock, Superchemiblock) and/or all blockers in an assay composition (for example diluent, detection composition) may be at least about 10 μg/mL, at least about 15 μg/mL, at least about 20 μg/mL, at least about 30 μg/mL, at least about 40 μg/mL, at least about 50 μg/mL, at least about 60 μg/mL, at least about 70 μg/mL, at least about 80 μg/mL, at least about 90 μg/mL, at least about 100 μg/mL, at least about 125 μg/mL, at least about 150 μg/mL, at least about 175 μg/mL, or at least about 200 μg/mL. In certain embodiments, for example, the concentration of one or more blockers (for example TRUblock, Superchemiblock) and/or all blockers in an assay composition may ranges from about 10 μg/mL to about 200 μg/mL (for example 10 μg/mL to about 100 μg/mL, 5 μg/mL to about 20 μg/mL, 50 μg/mL to about 100 μg/mL).

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems that are ultrasensitive and have very low limits of quantification and/or limits of detection (for example in the low pg/mL range). In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may be used to provide statistically significant and/or meaningful results regarding a measure of the concentration of the panels of two or more biomarkers associated with brain injury and/or neurodegeneration. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may have a limit of detection and/or a limit of quantification of less than about or about 500 pg/mL, less than about or about 250 pg/mL, less than about or about 100 pg/mL, less than about or about 50 pg/mL, less than about or about 40 pg/mL, less than about or about 30 pg/mL, less than about or about 20 pg/mL, less than about or about 10 pg/mL, less than about or about 8 pg/mL, less than about or about 6 pg/mL, less than about or about 5 pg/mL, less than about or about 4 pg/mL, less than about or about 3 pg/mL, less than about or about 2 pg/mL, less than about or about 1 pg/mL, less than about or about 0.8 pg/mL, less than about or about 0.7 pg/mL, less than about or about 0.6 pg/mL, less than about or about 0.5 pg/mL, less than about or about 0.4 pg/mL, less than about or about 0.3 pg/mL, less than about or about 0.2 pg/mL, less than about or about 0.1 pg/mL, less than about or about 0.08 pg/mL, less than about or about 0.06 pg/mL, less than about or about 0.05 pg/mL, less than about or about 0.04 pg/mL, less than about or about 0.02 pg/mL, less than about or about 0.01 pg/mL, or less than about or about 0.005 pg/mL for at least some (for example each) of the biomarkers. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may have a limit of quantification and/or a limit of detection between about 100 pg/mL and about 0.01 pg/mL, between about 50 pg/mL and about 0.02 pg/mL, or between about 25 pg/mL and about 0.02 pg/mL, between about 10 pg/mL and about 0.02 pg/mL for at least some (for example each) of the biomarkers.

In certain embodiments, for example, an LOQ and/or LOD may differ for one or more (for example each) of the biomarkers determined with the same assay and/or when two or more biomarkers are determined together in a single assay and/or from a single sample. In certain embodiments, for example, the LOD for Tau may be equal to or less than about 0.02 pg/mL and/or the LOQ for Tau may be equal to or less than about 0.1 pg/mL (for example equal to or less than about 0.06 pg/mL), for example when measured with one or more other biomarkers. In certain embodiments, for example, the LOD for NF-L may be equal to or less than about 0.2 pg/mL (for example equal to or less than about 0.1 pg/mL) and/or the LOQ for NF-L may be equal to or less than about 1.0 pg/mL (for example equal to or less than about 0.4 pg/mL, equal to or less than about 0.3 pg/mL), for example when measured with one or more other biomarkers. In certain embodiments, for example, the LOD for GFAP may be equal to or less than about 0.3 pg/mL and/or the LOQ for GFAP may be equal to or less than about 1.0 pg/mL (for example equal to or less than about 0.5 pg/mL), for example when measured with one or more other biomarkers. In certain embodiments, for example, the LOD for UCH-L1 may be equal to or less than about 5 pg/mL (for example equal to or less than about 2 pg/mL) and/or the LOQ for UCH-L1 may be equal to or less than about 10 pg/mL (for example equal to or less than about 5 pg/mL), for example when measured with one or more other biomarkers.

The terms “limit of detection” (or LOD) and “limit of quantification” (or LOQ) are given their ordinary meaning in the art. The LOD refers to the lowest analyte concentration likely to be reliably distinguished from background noise and at which detection is feasible. The LOD as used herein is defined as three standard deviations (SD) above background noise. The LOQ refers to the lowest concentration at which the analyte can not only be reliably detected but at which some predefined goals for bias and imprecision are met. Generally, as is used herein, the LOQ refers to the lowest concentration above the LOD wherein the coefficient of variation (CV) of the measured concentrations less than about 20%.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise comparing the levels of the one or more biomarkers with levels of the biomarkers obtained from a certain population of individuals. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise comparing the levels of the one or more biomarkers with levels of the biomarkers obtained from a population of individuals having a certain gender, age, ethnicity, health status, disease, phenotype, and/or genotype. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise comparing the levels of the one or more biomarkers with levels of the biomarkers obtained from a population of healthy individuals. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise comparing the levels of the one or more biomarkers with levels of the biomarkers obtained from a population of individuals with a history of one/or more brain injury events. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise collecting a sample from the patient (for example a capillary blood sample obtained by a heel prick or a finger prick). In certain embodiments, for example, the sample may be collected after a suspected brain injury. In certain embodiments, for example, the sample may be collected after an event creating a risk (for example a heightened risk) of brain injury (for example child birth or detonation of an explosive) or an event prone to causing brain injury. In certain embodiments, for example, the sample may be collected bwithin a certain timeframe of the brain injury or suspected brain injury. In certain embodiments, for example, the timeframe may be selected such that a measure of the concentration of the biomarkers in the sample becomes statistically significant. In certain embodiments, for example, the period of time between the brain injury or suspected brain injury and collection of the blood sample from the patient may account for any lag time required for the biomarkers to cross the blood brain barrier (BBB). Non-limiting examples of suitable periods of time in which a sample may be obtained from the patient include 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 18 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 4 days, 5 days, 6 days, 7 days, or more. In certain embodiments, for example, the duration of time between suspected brain injury and sample collection may be at least 60 hours or at least 72 hours. In certain embodiments, for example, the duration of time may be between 12 hours and 7 days, between 24 hours and 4 days, between 2 days and 4 days, or between 3 days and 4 days. In certain embodiments, for example, the sample may be obtained from the patient within a short timeframe following the brain injury or suspected brain injury. For example, the sample may be obtained from the patient within 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, or 12 hours of the brain injury. In certain embodiments, for example, the sample may be obtained within 6 hours of the brain injury. In certain embodiments, for example, the sample collection may occur months following the brain injury in order to assess long-term effects. In certain embodiments, for example, the samples may be collected 14 days, 1 month, 3 month, 6 months, 9 months, or more, following brain injury.

In certain embodiments, for example, the sample obtained from the patient may be from any suitable bodily source. In certain embodiments, for example, the sample may be a CSF fluid sample. In certain embodiments, for example, the sample may be exclusive of CSF fluid. In certain embodiments, for example, the sample may be blood (for example venous blood or capillary blood) or a blood product (for example whole blood, plasma, serum, etc.). In certain embodiments, for example, the sample may be a urine or a saliva sample. In certain embodiments, for example, the sample may be analyzed directly (for example without the need for extraction of the biomarker from the fluid sample) and/or with dilution (for example addition of a buffer or agent to the sample). In certain embodiments, for example, the sample may be obtained from dried physiological fluid (for example by rehydration and optionally dilution, elution, for by obtaining a supernatant fluid from a dried physiological fluid) such as a dried blood spot. Those of ordinary skill in the art will be aware of suitable systems and methods for obtaining a sample from a patient. In addition to the biomarkers specifically mentioned herein, those of ordinary skill will be aware of other suitable biomarkers to use in connection with the methods described herein. In certain embodiments, for example, biomarkers detected and/or quantified by the methods, tests, protocol, assays, kits, or systems may comprise, without limitation, neuron specific neuronal enolase (NSE), β-site aPP-cleaving enzyme 1 (BACe1), S100B, myelin basic protein (MBP), growth associated protein 43, glutamine synthetase, GFAP, glycine transporter (for example GLYT1, GLYT2), neuron specific glycoprotein (for example GP50), calpain, neurofibrillary protein, heat shock protein 72, beta-amyloid precursor proteins, calbindin D-28K, proteolipid protein, myeline associated glycoprotein, neurofilament H, creatine kinase protein (for example CK-BB), tau proteins (including phosphorylated taus such as p-tau-81 or p-tau-231), and endothelium membrane proteins (for example thrombomodulin).

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise detecting and/or quantifying a panel of biomarkers. In certain embodiments, for example, the panel of biomarkers may include at least one species of tau protein. Various forms and/or combinations of tau proteins are contemplated for use as a target biomarker with the methods described herein, including isoforms and short isoforms, for example, ranging from tau 23 (352a.a, “ON3R”, wherein R indicates the number of repeats and N indicates the number or amino terminal inserts, as will be understood by those of ordinary skill in the art) to tau 40 (441a.a, “2N4R”). There are six known naturally-occurring tau proteins, the sequences of which are well known in the art. The six tau proteins include tau 23 (352, ON3R), tau 24 (383, ON4R), tau 37 (381, 1N3R), tau 34 (412, 1N4R), tau 39 (410, 2N3R), tau 40 (441, 2N4R), and/or combinations thereof. In certain embodiments, for example, at least some of the tau proteins may be phosphorylated.

Those of ordinary skill in the art will understand that determination of a biomarker in a sample may comprise determining a measure of the concentration a single isoform of a biomarker, or alternatively, may comprise determining a measure of the concentration of a plurality (for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10) of isoforms of the biomarker. In certain embodiments, for example, a measure of the concentration of tau protein employed in the methods described herein may be a measure of the concentration of a single isoform of tau protein in the sample, or alternatively, a measure of the concentration of tau protein employed in the algorithms and methods described herein may be a measure of the concentration of a plurality of forms of tau proteins in the sample.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise using an immunoassay to determine a measure of the concentration of two or more biomarkers. In certain embodiments, for example, the immunoassay may utilize an antibody as a detection molecule. In general, any suitable antibodies that differentially and/or selectively binds a biomarker may be used.

An immunoassay is a biochemical test that measures the presence or concentration of a molecule of interest (for example a macromolecule such as a protein) in a sample through the use of an antibody or immunoglobulin. Typically, an antibody specific to the molecule of interest interacts with the molecule in an immunoassay. The antibody can be labeled, directly or indirectly such that those bound to the molecule could release a detectable signal. Presence or concentration of the molecule of interest can be determined based on the level of the detectable signal. Certain embodiments may provide, for example, an immunoassay using one or more types of labels including, without limitation, enzymes, radioactive isotopes, DNA reporters, fluorogenic reporters, electrochemiluminescent tags, all of which are well known in the art. In certain embodiments, for example, the immunoassay may amplify a signal via a catalyst (for example an enzyme). In certain embodiments, for example, the immunoassay may be exclusive of a label.

In certain embodiments, for example, the immunoassay may be used to detect an antigen of interest (for example NF-L, tau protein, GFAP, UCH-L1, etc.). In certain embodiments, for example, the immunoassay may comprise a protocol that comprises certain standard techniques known in the art. In certain embodiments, for example, the immunoassay may be a competitive immunoassay. In certain embodiments, for example, the immunoassay may be a one-site non-competitive assay. In certain embodiments, for example, the immunoassay may be a two-site noncompetitive assay (for example a sandwich assay). In certain embodiments, for example, the immunoassay may comprise multiple steps with reagents being added and washed away or separated at different points in the assay (for example a heterogeneous immunoassay). In certain embodiments, for example, the immunoassay may be carried out simply by mixing the reagents and sample and making a physical measurement (for example a homogenous immunoassay).

In a preferred embodiment, for example, the immunoassay may be an enzyme-linked immunosorbent assay (ELISA). In certain embodiments, for example, the immunoassay may be a digital assay (for example a digital ELISA). In certain embodiments, for example, the digital ELISA may incorporate single molecule array technology (for example digital immunoassay technology sold under the Simoa trademark) as described herein. Additional details regarding single molecule array technologies are described herein.

The basic nature of the ELISA format is generally well known in the art. The inventive ELISA type assays used in certain embodiments of the detection methods described herein can incorporate a variety of formats known in the art, including direct ELISA, Sandwich ELISA, competitive ELISA, and multiple and ready-to-use ELISA. In a typical “indirect” ELISA, an antibody having specificity for the antigen of interest is immobilized on a solid surface (for example the wells of a standard microtiter assay plate, or the surface of a microbead or a microarray) and a sample comprising, for example bodily fluid or substances extracted from stool samples, to be tested for the presence of the antigen is brought into contact with the immobilized antibody. Any antigen of interest in the sample will bind to the immobilized antibody. The bound antibody/antigen complexes may then be detected using any suitable method. In one embodiment, a second antibody, which specifically recognizes an epitope of the antigen, which may be different from the epitope recognized by the immobilized antibody, is used to detect the antibody/antigen complexes. The second antibody may be usually labelled with a detectable marker (directly or indirectly). In some examples, the maker can be an enzyme such as peroxidase, alkaline phosphatase, or galactosidase, allowing quantitative detection by the addition of a substrate for the enzyme which generates a detectable product, for example a colored, chemiluminescent or fluorescent product. Other types of detectable labels known in the art may be used with equivalent effect. In other examples, the second antibody may be labeled with a member of a receptor/ligand pair, for example, biotin. An enzyme conjugate comprising an enzyme conjugated with the other member of the receptor/ligand pair, for example streptavidin, can be brought into contact with the second antibody. A substrate of the enzyme may then be added to produce a product that releases a detectable signal.

Generally, the methods employed have low limits of detection and/or limits of quantification as compared to bulk analysis techniques (for example ELISA methods). The use of assay methods that have low limits of detection and/or limits of quantification allows for correlations to be made between the various parameters discussed above and a method of treatment and/or diagnostic indication that may otherwise not be determinable and/or apparent.

An antibody (interchangeably used in plural form) is an immunoglobulin molecule capable of specific binding to a target, such as NF-L, Tau, GFAP, and UCH-L1, through at least one antigen recognition site, located in the variable region of the immunoglobulin molecule. As used herein, the term “antibody” encompasses not only intact (i.e., full-length) polyclonal or monoclonal antibodies, but also antigen-binding fragments thereof (such as Fab, Fab′, F(ab′)2, Fv), single chain (scFv), mutants thereof, fusion proteins comprising an antibody portion, humanized antibodies, chimeric antibodies, diabodies, linear antibodies, single chain antibodies, multispecific antibodies (for example bispecific antibodies) and any other modified configuration of the immunoglobulin molecule that comprises an antigen recognition site of the required specificity, including glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. An antibody includes an antibody of any class, such as IgD, IgE, IgG, IgA, or IgM (or sub-class thereof), and the antibody need not be of any particular class. Depending on the antibody amino acid sequence of the constant domain of its heavy chains, immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), for example IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2. The heavy-chain constant domains that correspond to the different classes of immunoglobulins are called alpha, delta, epsilon, gamma, and mu, respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known. The antibodies described herein can be murine, rat, human, or any other origin (including chimeric or humanized antibodies).

In certain embodiments, for example, the analyte antibodies described herein may have a suitable binding affinity to the antigen. As used herein, “binding affinity” refers to the apparent association constant or K_(A). The K_(A) is the reciprocal of the dissociation constant (K_(D)). The antibody described herein may have a binding affinity (K_(D)) of at least 10⁻⁵, 10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹, 10⁻¹⁰ M, or lower. An increased binding affinity corresponds to a decreased K_(D). Higher affinity binding of an antibody to a first target relative to a second target can be indicated by a higher K_(A) (or a smaller numerical value K_(D)) for binding the first target than the K_(A) (or numerical value K_(D)) for binding the second target. In such cases, the antibody has specificity for the first target relative to the second target. Differences in binding affinity (for example for specificity or other comparisons) can be at least 1.5, 2, 3, 4, 5, 10, 15, 20, 37.5, 50, 70, 80, 91, 100, 500, 1000, 10,000 or 10⁵ fold.

Binding affinity can be determined by a variety of methods including equilibrium dialysis, equilibrium binding, gel filtration, ELISA, surface plasmon resonance, or spectroscopy (for example using a fluorescence assay). Exemplary conditions for evaluating binding affinity are in HBS-P buffer (10 mM HEPES pH7.4, 150 mM NaCl, 0.005% (v/v) Surfactant P20). These techniques can be used to measure the concentration of bound binding protein as a function of target protein concentration. The concentration of bound binding protein ([Bound]) is related to the concentration of free target protein ([Free]) and the concentration of binding sites for the binding protein on the target where (N) is the number of binding sites per target molecule by the following equation:

[Bound]=[N][Free]/(K _(D)+[Free])

It is not always necessary to make an exact determination of K_(A), though, since sometimes it is sufficient to obtain a quantitative measurement of affinity, for example determined using a method such as ELISA or FACS analysis, which is proportional to K_(A), and thus can be used for comparisons, such as determining whether a higher affinity is, for example 2-fold higher, to obtain a qualitative measurement of affinity, or to obtain an inference of affinity, for example by activity in a functional assay, for example an in vitro or in vivo assay.

In certain embodiments, for example, the antibodies used in the detection assays described herein may differentially bind one biomarker associated with brain injury and/or neurodegeneration over another such biomarker. An antibody that “differentially binds” to a first target or a first epitope as relative to a second target or a second epitope refers to an antibody that has different binding affinities to the first and second targets or different binding affinities to the first and second epitopes. In certain embodiments, for example, an antibody may have a much higher binding affinity to the first target/epitope as relative to the second target/epitope, or vice versa, for example at least 2-fold higher, 5-fold higher, 10-fold higher, 50-fold higher, 100-fold higher, 200-fold higher, 500-fold higher, 1,000-fold higher, or 10,000-fold higher. In other examples, the antibody may have a much lower binding affinity to the first target/epitope as relative to the second target/epitope, or vice versa, for example at least 2-fold lower, 5-fold lower, 10-fold lower, 50-fold lower, 100-fold lower, 200-fold lower, 500-fold lower, 1,000-fold lower, or 10,000-fold lower.

In certain embodiments, for example, the antibodies used in the detection assays described herein may specifically bind one biomarker associated with brain injury and/or neurodegeneration over another such biomarker. An antibody “specifically binds” to a target antigen if it binds with greater affinity, avidity, more readily, and/or with greater duration than it binds to other substances. It is also understood by reading this definition that, for example, an antibody that specifically binds to a first target antigen may or may not specifically or preferentially bind to a second target antigen. As such, “specific binding” or “preferential binding” does not necessarily require (although it can include) exclusive binding. Generally, but not necessarily, reference to binding means preferential binding.

Antibodies capable of binding biomarkers associated with brain injury and/or neurodegeneration can be made by any method known in the art and/or are commercially available. See, for example, Harlow and Lane, (1988) Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, New York.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining a measure of the concentration of a panel of at least one biomarker in one or more samples obtained from a patient following a suspected brain injury. In certain embodiments, for example, a diagnosis, prognostic indication of the patient's recovery, and/or determining a course of treatment may be based at least in part on the measure of the concentration of the at least one biomarker present in the one or more samples. In certain embodiments, for example, following determining the measure of the concentration of the biomarkers, the measure of the concentration may be compared with a predefined level of the biomarker from a population of healthy individuals. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise comparing the measure of the concentration of NF-L and at least one other biomarker (for example one or more of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE) with levels of NF-L and the at least one other biomarker (for example levels based on measurements taken from samples obtained from a population of healthy individuals).

Certain embodiments may provide, for example, kits for use in determining a measure of the concentration of at least one biomarker in a sample. In certain embodiments, for example, the at least one biomarker may be at least two biomarkers, wherein a first biomarker of the at least two biomarkers may be NF-L and at least a second of the at least two biomarkers may be at least one other biomarker selected from the group consisting of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the kit may be for measuring concentration of a biomarker panel comprising at least Tau, GFAP, UCH-L1, and NF-L (for example comprising GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE). In certain embodiments, for example, the kit may comprise a plurality of capture objects (for example beads, optionally magnetic beads), each having a binding surface comprising a plurality of capture components. In certain embodiments, for example, the plurality of capture components may comprise a plurality of an antibodies having specific affinity for the one or more biomarkers being detected. In certain embodiments, for example, each capture object (for example bead) may comprise a plurality of types of capture objects, each type of capture object having specific affinity for a particular biomarker (for example a plurality of antibodies having specific affinity for NF-L and a plurality of antibodies having specific affinity for at least one other biomarker selected from the group consisting of, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE). In certain embodiments, for example, the kit may comprise a plurality of types of binding ligands having specific affinity for the at least one biomarker. In certain embodiments, for example, the binding ligands may be directly or indirectly detectable. In certain embodiments, for example, the kit may comprise a plurality of a first type of binding ligand having affinity for NF-L and a plurality of a second type of binding ligand having affinity for at least one other biomarker selected from the group consisting of, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the kit may comprise i) a plurality of capture objects, each having a binding surface comprising a plurality of capture components; ii) a plurality of a first type of binding ligand having affinity for NF-L; and iii) a plurality of a second type of binding ligand and a third type of binding ligand having affinity for at least two other biomarker selected from the group consisting of, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. In certain embodiments, for example, the kit may comprise i) a plurality of capture objects, each having a binding surface comprising a plurality of capture components; ii) a plurality of a first type of binding ligand having affinity for NF-L; iii) a plurality of a second type of binding ligand having affinity for GFAP; iv) a plurality of a third type of binding ligand having affinity for UCH-L1; and v) a plurality of a fourth type of binding ligand having affinity for Tau. In certain embodiments, for example, the kit may comprise one or more components for performing the assays. In certain embodiments, for example, the kit may comprise an enzyme label substrate for indirect detection of a binding ligand. In certain embodiments, for example, the kit may comprise an instruction manual providing guidance for using the kit to perform any one of the detection assay provided herein.

Exemplary Assay Methods and Systems

Certain embodiments, for example, may provide methods, tests, protocol, assays, kits, or systems having low limits of detection and/or limits of quantification as compared to bulk analysis techniques (for example modified ELISA methods). In certain embodiments, for example, use of the provided methods, tests, protocol, assays, kits, or systems may enable one or more methods of treatment and/or diagnostic indication that may otherwise not be determinable and/or apparent.

In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample that may be substantially accurately determined may be less than about or about 5000 fM, less than about or about 3000 fM, less than about or about 2000 fM, less than about or about 1000 fM, less than about or about 500 fM, less than about or about 300 fM, less than about or about 200 fM, less than about or about 100 fM, less than about or about 50 fM, less than about or about 25 fM, less than about or about 10 fM, less than about or about 5 fM, less than about or about 2 fM, less than about or about 1 fM, less than about or about 0.5 fM, less than about or about 0.1 fM, or less. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample that may be substantially accurately determined may be between about 5000 fM and about 0.1 fM, between about 3000 fM and about 0.1 fM, between about 1000 fM and about 0.1 fM, between about 1000 fM and about 1 fM, between about 100 fM and about 1 fM, between about 100 fM and about 0.1 fM, or the like. In certain embodiments, for example, a measure of the concentration of analyte molecules or particles in a fluid sample may be considered to be substantially accurately determined if the measured concentration of the biomarker molecules in the fluid sample may be within about 10% of the actual (for example true) concentration of the biomarker molecules in the fluid sample. In certain embodiments, for example, the measured concentration of the biomarker molecules in the fluid sample may be within about 5%, within about 4%, within about 3%, within about 2%, within about 1%, within about 0.5%, within about 0.4%, within about 0.3%, within about 0.2% or within about 0.1%, of the actual concentration of the biomarker molecules in the fluid sample. In certain embodiments, for example, a measure of the concentration determined may differ from the true (for example actual) concentration by no greater than about 20%, no greater than about 15%, no greater than 10%, no greater than 5%, no greater than 4%, no greater than 3%, no greater than 2%, no greater than 1%, or no greater than 0.5%. In certain embodiments, for example, the accuracy of the assay method may be determined by determining a measure of the concentration of biomarker molecules in a fluid sample of a known concentration using the selected assay method.

Certain embodiments may provide, for example, an assay method comprising: spatially segregating biomarker molecules into a plurality of locations to facilitate detection/quantification, such that each location comprises/contains either zero or one or more biomarker molecules. In certain embodiments, for example, the locations may be configured in a manner such that each location can be individually addressed. In certain embodiments, for example, a measure of the concentration of biomarker molecules in a fluid sample may be determined by detecting biomarker molecules immobilized with respect to a binding surface having affinity for at least one type of biomarker molecule. In certain embodiments, for example, the binding surface may form (for example a surface of a well/reaction vessel on a substrate) or be contained within (for example a surface of a capture object, such as a bead, contained within a well) one of a plurality of locations (for example a plurality of wells/reaction vessels) on a substrate (for example plate, dish, chip, optical fiber end, etc.). In certain embodiments, for example, at least a portion of the locations may be addressed and a measure indicative of the number/percentage/fraction of the locations containing at least one biomarker molecule may be made. In certain embodiments, for example, based upon the number/percentage/fraction, a measure of the concentration of biomarker molecules in the fluid sample may be determined. In certain embodiments, for example, the measure of the concentration of biomarker molecules in the fluid sample may be determined by a digital analysis method/system. In certain embodiments, for example, the measure of the concentration of biomarker molecules in the fluid sample may be determined by a digital analysis method/system employing Poisson distribution adjustment. In certain embodiments, for example, the measure of the concentration of biomarker molecules in the fluid sample may be determined by a digital analysis method/system based at least in part on a measured intensity of a signal. In certain embodiments, for example, the assay method (or apparatus or systems performing at least a portion of the assay method) may be automated.

Any of the methods, tests, protocol, assays, kits, or systems may employ one or more of the methods and systems for spatially segregating analyte molecules (for example biomarkers) described in U.S. Patent Application Publication No. US-2007-0259448 (Ser. No. 11/707,385), filed Feb. 16, 2007, entitled “METHODS AND ARRAYS FOR TARGET ANALYTE DETECTION AND DETERMINATION OF TARGET ANALYTE CONCENTRATION IN SOLUTION,” by Walt et al.; U.S. Patent Application Publication No. US-2007-0259385 (Ser. No. 11/707,383), filed Feb. 16, 2007, entitled “METHODS AND ARRAYS FOR DETECTING CELLS AND CELLULAR COMPONENTS IN SMALL DEFINED VOLUMES,” by Walt et al.; U.S. Patent Application Publication No. US-2007-0259381 (Ser. No. 11/707,384), filed Feb. 16, 2007, entitled “METHODS AND ARRAYS FOR TARGET ANALYTE DETECTION AND DETERMINATION OF REACTION COMPONENTS THAT AFFECT A REACTION,” by Walt et al.; International Patent Publication No. WO 2009/029073 (International Patent Application No. PCT/US2007/019184), filed Aug. 30, 2007, entitled “METHODS OF DETERMINING THE CONCENTRATION OF AN ANALYTE IN SOLUTION,” by Walt et al.; U.S. Patent Application Publication No. US-2010-0075862 (Ser. No. 12/236,484), filed Sep. 23, 2008, entitled “HIGH SENSITIVITY DETERMINATION OF THE CONCENTRATION OF ANALYTE MOLECULES OR PARTICLES IN A FLUID SAMPLE,” by Duffy et al.; U.S. Patent Application Publication No. US-2010-00754072 (Ser. No. 12/236,486), filed Sep. 23, 2008, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES ON SINGLE MOLECULE ARRAYS,” by Duffy et al.; U.S. Patent Application Publication No. US-2010-0075439 (Ser. No. 12/236,488), filed Sep. 23, 2008, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES BY CAPTURE-AND-RELEASE USING REDUCING AGENTS FOLLOWED BY QUANTIFICATION,” by Duffy et al.; International Patent Publication No. WO2010/039179 (International Patent Application No. PCT/US2009/005248), filed Sep. 22, 2009, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR ENZYMES,” by Duffy et al.; U.S. Patent Application Publication No. US-2010-0075355 (Ser. No. 12/236,490), filed Sep. 23, 2008, entitled “ULTRA-SENSITIVE DETECTION OF ENZYMES BY CAPTURE-AND-RELEASE FOLLOWED BY QUANTIFICATION,” by Duffy et al.; U.S. patent application Ser. No. 12/731,130, filed Mar. 24, 2010, published as US-2011-0212848 on Sep. 1, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al.; International Patent Application No. PCT/US2011/026645, filed Mar. 1, 2011, published as WO 2011/109364 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al.; International Patent Application No. PCT/US2011/026657, filed Mar. 1, 2011, published as WO 2011/109372 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES USING DUAL DETECTION METHODS,” by Duffy et al.; U.S. patent application Ser. No. 12/731,135, filed Mar. 24, 2010, published as US-2011-0212462 on Sep. 1, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES USING DUAL DETECTION METHODS,” by Duffy et al.; International Patent Application No. PCT/US2011/026665, filed Mar. 1, 2011, published as WO 2011/109379 on Sep. 9, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Rissin et al.; U.S. patent application Ser. No. 12/731,136, filed Mar. 24, 2010, published as US-2011-0212537 on Sep. 1, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Duffy et al.; U.S. patent application Ser. No. 13/035,472, filed Feb. 25, 2011, published as US 2012-0196774, entitled “SYSTEMS, DEVICES, AND METHODS FOR ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES,” by Fournier et al.; or U.S. patent application Ser. No. 13/037,987, filed Mar. 1, 2011, published as US-2011-0245097 on Oct. 6, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Rissin et al.; each herein incorporated by reference.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems comprising spatially segregating biomarker molecules for detecting and/or quantifying the biomarker molecules (for example in a sample). In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise immobilizing a plurality of biomarker molecules with respect to a plurality of capture objects (for example beads) that each include a binding surface having affinity for at least one type of biomarker. In certain embodiments, for example, the capture objects may comprise a plurality of beads comprising a plurality of capture components (for example an antibody having specific affinity for a biomarker of interest, etc.). In certain embodiments, for example, at least a portion of the capture objects (for example at least a portion that is associated with at least one biomarker molecule) may be spatially separated/segregated into a plurality of locations, and at least some of the locations may be addressed/interrogated (for example using an imaging system). In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample may be determined based on the information received when addressing the locations (for example using the information received from the imaging system and/or processed using a computer implemented control system). In certain embodiments, for example, a measure of the concentration may be based at least in part on the number of locations determined to contain a capture object that is or was associated with at least one biomarker molecule. In certain embodiments, for example, a measure of the concentration may be based at least in part on an intensity level of at least one signal indicative of the presence of a plurality of biomarker molecules and/or capture objects associated with a biomarker molecule at one or more of the addressed locations.

In certain embodiments, for example, a number/percentage/fraction of locations containing a capture object but not containing a biomarker molecule may also be determined and/or the number/percentage/fraction of locations not containing any capture object may also be determined. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample may be based at least in part on a ratio of the number of locations determined to contain a capture object associated with a biomarker molecule to the total number of locations determined to contain a capture object not associated with a biomarker molecule. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample a measure of the concentration of biomarker molecule in the fluid sample may be based at least in part on the ratio of the number of locations determined to contain a capture object associated with a biomarker molecule to the number of locations determined to not contain any capture objects. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample, a measure of the concentration of biomarker molecule in the fluid sample may be based at least in part on the ratio of the number of locations determined to contain a capture object associated with a biomarker molecule to the number of locations determined to contain a capture object. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample, a measure of the concentration of biomarker molecule in the fluid sample may be based on a combination of two or more of the foregoing measures. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample, a measure of the concentration of biomarker molecule in the fluid sample may be based may be based at least in part on the ratio of the number of locations determined to contain a capture object and a biomarker molecule to the total number of locations addressed and/or analyzed. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample, a measure of the concentration of biomarker molecule in the fluid sample may be based on a combination of two or more of the foregoing measures.

In certain embodiments, for example, at least some of the plurality of capture objects (for example at least some associated with at least one biomarker molecule) may be spatially separated into a plurality of locations, for example, a plurality of reaction vessels in an array format. The plurality of reaction vessels may be formed in, on and/or of any suitable material. In certain embodiments, for example, the reaction vessels may be sealed or may be formed upon the mating of a substrate with a sealing component. In certain embodiments, for example, (for example where quantization of the capture objects associated with at least one biomarker molecule is desired), the partitioning of the capture objects may be performed such that at least some (for example a statistically significant fraction; for example as described in International Patent Application No. PCT/US2011/026645, filed Mar. 1, 2011, published as WO 2011/109364 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al., herein incorporated by reference) of the reaction vessels comprise at least one or, in certain cases, only one capture object associated with at least one biomarker molecule and at least some (for example a statistically significant fraction) of the reaction vessels comprise an capture object not associated with any biomarker molecules. In certain embodiments, for example, the capture objects associated with at least one biomarker molecule may be quantified, thereby allowing for the detection and/or quantification of biomarker molecules in the fluid sample by any of the techniques described herein.

Certain embodiments may provide, for example, an assay method, wherein: a sample fluid containing or suspected of containing biomarker molecules is provided; and an assay consumable comprising a plurality of assay sites is exposed to the sample fluid. In certain embodiments, for example, the biomarker molecules may be provided in a manner (for example at a concentration) such that a statistically significant fraction of the assay sites contain a single biomarker molecule and a statistically significant fraction of the assay sites do not contain any biomarker molecules. In certain embodiments, for example, the assay sites may be exposed to a variety of reagents (for example using a reagent loader) and or rinsed. In certain embodiments, for example, the assay sites may then optionally be sealed and imaged (see, for example, U.S. patent application Ser. No. 13/035,472, filed Feb. 25, 2011, published as US 2012-0196774, entitled “SYSTEMS, DEVICES, AND METHODS FOR ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES,” by Fournier et al.). In certain embodiments, for example, the images may be analyzed (for example using a computer implemented control system) such that a measure of the concentration of the biomarker molecules in the fluid sample may be obtained, based at least in part, by determination of the number/fraction/percentage of assay sites which contain a biomarker molecule and/or the number/fraction/percentage of sites which do not contain any biomarkers molecules. In certain embodiments, for example, the biomarker molecules may be provided in a manner (for example at a concentration) such that at least some assay sites comprise more than one biomarker molecule. In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample may be obtained at least in part on an intensity level of at least one signal indicative of the presence of a plurality of biomarkers molecules at one or more of the assay sites.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise exposing the fluid sample to a plurality of capture objects (for example beads). In certain embodiments, for example, at least a portion of the biomarker molecules may be immobilized with respect to a bead. In certain embodiments, for example, the biomarker molecules may be provided in a manner (for example at a concentration) such that a statistically significant fraction of the beads associate with a single biomarker molecule and a statistically significant fraction of the beads do not associate with any biomarker molecules. In certain embodiments, for example, at least a portion of the plurality of beads (for example those associated with a single biomarker molecule or not associated with any biomarker molecules) may then be spatially separated/segregated into a plurality of assay sites (for example of an assay consumable). In certain embodiments, for example, the assay sites may optionally be exposed to a variety of reagents and/or rinsed. In certain embodiments, for example, at least a portion of the assay sites may then be addressed to determine the number of assay sites containing a biomarker molecule. In certain embodiments, for example, the number of assay sites containing a bead not associated with a biomarker molecule, the number of assay sites not containing a bead and/or the total number of assay sites addressed may also be determined. In certain embodiments, for example, the determined total number of assay sites may then be used to determine a measure of the concentration of biomarker molecules in the fluid sample. In certain embodiments, for example, more than one biomarker molecule may associate with a bead and/or more than one bead may be present in an assay site. In certain embodiments, for example, the plurality biomarker molecules may be exposed to at least one additional reaction component prior to, concurrent with, and/or following spatially separating at least some of the biomarker molecules into a plurality of locations.

In certain embodiments, for example, the biomarker molecules may be directly detected or indirectly detected. In certain embodiments, for example, one or more of the biomarker molecules may be directly detected via a molecule or moiety that is directly interrogated and/or detected (for example by one or more fluorescent entities attached to the one or more biomarker molecules). In certain embodiments, for example, one or more of the biomarker molecules may be indirectly detected by the presence of an additional component. In certain embodiments, for example, the biomarker molecules (for example optionally associated with a bead) may be exposed to at least one type of binding ligand. In certain embodiments, for example, the at least one type of binding ligand may be adapted to be directly detected (for example the at least one type of binding ligand may comprise a detectable molecule or moiety) or may be adapted to be indirectly detected (for example the at least one type of binding ligand may including a component that can convert a precursor labeling agent into a labeling agent). In certain embodiments, for example, a component of the at least one type of binding ligand may be adapted to be directly detected via a measurable property (for example a fluorescence emission, a color, etc.). In certain embodiments, for example, a component a component of the at least one type of binding ligand may facilitate indirect detection, for example, by converting a precursor labeling agent into a labeling agent (for example an agent that is detected in an assay). A “precursor labeling agent” is any molecule, particle, or the like, that can be converted to a labeling agent upon exposure to a suitable converting agent (for example an enzymatic component). A “labeling agent” is any molecule, particle, or the like, that facilitates detection, by acting as the detected entity, using a chosen detection technique. In certain embodiments, for example, the at least one type of binding ligand may comprise an enzymatic component (for example horseradish peroxidase, beta-galactosidase, alkaline phosphatase, etc.). In certain embodiments, for example, a first type of binding ligand may or may not be used in conjunction with one or more additional types of binding ligands (for example second type, etc.).

In certain embodiments, for example, the at least one type of binding ligand may comprise a plurality of types of binding ligands (for example a first type of binding ligand and at least a second type of binding ligand). In certain embodiments, for example, a first type of binding ligand may be configured to associate with a first type of biomarker molecule and a second type of binding ligand may be configured to associate with the first binding ligand. In certain embodiments, for example, both a first type of binding ligand and a second type of binding ligand may associate with the same or different epitopes of a single biomarker molecule. In certain embodiments, for example, at least one binding ligand may comprise an enzymatic component.

In certain embodiments, for example, a binding ligand and/or a biomarker may comprise an enzymatic component. In certain embodiments, for example, the enzymatic component may convert a precursor labeling agent (for example an enzymatic substrate) into a labeling agent (for example a detectable product). In certain embodiments, for example, a measure of the concentration of biomarker molecules in the fluid sample may be determined based at least in part by determining the number of locations containing a labeling agent (for example by relating the number of locations containing a labeling agent to the number of locations containing a biomarker molecule (or number of capture objects associated with at least one biomarker molecule to total number of capture objects)). Non-limiting examples of enzymes or enzymatic components include horseradish peroxidase, beta-galactosidase, and alkaline phosphatase. Other non-limiting examples of systems or methods for detection include embodiments where nucleic acid precursors are replicated into multiple copies or converted to a nucleic acid that can be detected readily, such as the polymerase chain reaction (PCR), rolling circle amplification (RCA), ligation, Loop-Mediated Isothermal Amplification (LAMP), etc. Such systems and methods will be known to those of ordinary skill in the art, for example, as described in “DNA Amplification: Current Technologies and Applications,” Vadim Demidov et al., 2004.

In certain embodiments, for example, the biomarker molecules may be exposed to a precursor labeling agent (for example enzymatic substrate) and the enzymatic substrate may be converted to a detectable product (for example fluorescent molecule) upon exposure to a biomarker molecule.

Certain embodiments may provide, for example, methods, tests, protocol, assays, kits, or systems that employ a variety of different components, steps, and/or other aspects that will be known and understood by those of ordinary skill in the art. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise determining at least one background signal determination. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may further comprise subtracting the background signal from other determinations. In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may comprise one more washings of capture objects to remove excess sample, reagents, and the like.

In certain embodiments, for example, the methods, tests, protocol, assays, kits, or systems may include the use of at least one binding ligand. In certain embodiments, for example, a measure of the concentration of biomarker molecules in a fluid sample may be based at least in part on comparison of a measured parameter to a calibration curve. In certain embodiments, for example, the calibration curve may be formed at least in part by determination at least one calibration factor.

In certain embodiments, for example, precursor labeling agents suspended and/or solubilized in a liquid may be employed. In certain embodiments, for example, the precursor labeling agents may be converted to labeling agents which are insoluble in the liquid. In certain embodiments, for example, the precursor labeling agents may be converted to labeling agents which become immobilized proximate a location (for example within the reaction vessel in which the labeling agent is formed). Such precursor labeling agents and labeling agents and their use are described in commonly owned U.S. Patent Application Publication No. US-2010-0075862 (Ser. No. 12/236,484), filed Sep. 23, 2008, entitled “HIGH SENSITIVITY DETERMINATION OF THE CONCENTRATION OF ANALYTE MOLECULES OR PARTICLES IN A FLUID SAMPLE,” by Duffy et al., incorporated herein by reference.

In certain embodiments, for example, a plurality of locations may be addressed and/or a plurality of capture objects and/or species/molecules/particles of interest may be detected substantially simultaneously. “Substantially simultaneously” when used in this context, refers to addressing/detection of the locations/capture objects/species/molecules/particles of interest at approximately the same time such that the time periods during which at least two locations/capture objects/species/molecules/particles of interest are addressed/detected overlap, as opposed to being sequentially addressed/detected, where they would not. Simultaneous addressing/detection may be accomplished by using various techniques, including optical techniques (for example CCD detector). In certain embodiments, for example, capture objects/species/molecules/particles may be spatially segregated into a plurality of discrete, resolvable locations. In certain embodiments, for example, the spatially segregated capture objects/species/molecules/particles may be detected substantially simultaneously by allowing multiple locations to be addressed substantially simultaneously. In certain embodiments, for example, individual species/molecules/particles may be associated with capture objects that are spatially segregated with respect to the other capture objects into a plurality of discrete, separately resolvable locations during detection. In certain embodiments, for example, the plurality of discrete, individual capture objects (and thus individual species/molecules/particles (for example biomarker molecules)) are separately resolved in the separately resolvable locations. In certain embodiments, for example, individual molecules/particles of a plurality of molecules/particles may be partitioned across a plurality of reaction vessels such that each reaction vessel contains zero or only one species/molecule/particle. In certain embodiments, for example, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, at least about 99.5% of all species/molecules/particles may be spatially separated with respect to other species/molecules/particles during detection. In certain embodiments, for example, a plurality of species/molecules/particles may be detected substantially simultaneously within a time period of less than about 1 second, less than about 500 milliseconds, less than about 100 milliseconds, less than about 50 milliseconds, less than about 10 milliseconds, less than about 1 millisecond, less than about 500 microseconds, less than about 100 microseconds, less than about 50 microseconds, less than about 10 microseconds, less than about 1 microsecond, less than about 0.5 microseconds, less than about 0.1 microseconds, or less than about 0.01 microseconds, less than about 0.001 microseconds, or less. In certain embodiments, for example, the plurality of species/molecules/particles may be detected substantially simultaneously within a time period of between about 100 microseconds and about 0.001 microseconds, between about 10 microseconds and about 0.01 microseconds, or less.

In certain embodiments, for example, the locations may be optically interrogated. In certain embodiments, for example, locations exhibiting changes in their optical signature may be identified by a conventional optical train and optical detection system. Depending on the detected species (for example type of fluorescence entity, etc.) and the operative wavelengths, optical filters designed for a particular wavelength may be employed for optical interrogation of the locations. In certain embodiments, for example, a system for optical interrogation may comprise more than one light source and/or a plurality of filters to adjust the wavelength and/or intensity of the more than one light source. In certain embodiments, for example, the optical signal from a plurality of locations may be captured using a CCD camera.

In certain embodiments, for example, the plurality of reaction vessels may be sealed (for example after the introduction of the biomarker molecules, binding ligands, and/or precursor labeling agent). In certain embodiments, for example, the plurality of reaction vessels may be sealed by mating of the second substrate with a sealing component. In certain embodiments, for example, the plurality of reaction vessels may be sealed with a sealing fluid (for example a silicone oil sealing fluid). In certain embodiments, for example, the sealing of the reaction vessels may be such that the contents of each reaction vessel cannot escape the reaction vessels during performance of an assay. In certain embodiments, for example, the reaction vessels may be sealed after the addition of the biomarker molecules and, optionally, at least one type of precursor labeling agent to facilitate detection of the biomarker molecules. In certain embodiments, for example, by sealing the contents in some or each reaction vessel, a reaction to produce the detectable labeling agents may proceed within the sealed reaction vessels, thereby producing a detectable amount of labeling agents that is retained in the reaction vessel for detection purposes.

In certain embodiments, for example, the plurality of locations may be formed using a variety of methods and/or materials. In certain embodiments, for example, the plurality of locations may comprise a plurality of reaction vessels/wells on a substrate. In certain embodiments, for example, the plurality of reaction vessel may be formed as an array of depressions on a first surface. In certain embodiments, for example, the plurality of reaction vessels may be formed by mating a sealing component comprising a plurality of depressions with a substrate that may either have a featureless surface or include depressions aligned with those on the sealing component. Any of the device components, for example, the substrate or sealing component, may be fabricated from a compliant material, for example an elastomeric polymer material, to aid in sealing. The surfaces may be or made to be hydrophobic or contain hydrophobic regions to minimize leakage of aqueous samples from the microwells. In certain embodiments, for example, the reactions vessels may be configured to receive and contain only a single capture object (for example a single bead such as a paramagnetic bead).

In certain embodiments, for example, the reaction vessels may all have approximately the same volume. In certain embodiments, for example, the reaction vessels may have differing volumes. In certain embodiments, for example, the volume of each individual reaction vessel may be selected to be appropriate to facilitate an assay protocol. In certain embodiments, for example, the number of capture objects used for biomarker capture contained in each vessel may be limited to a small number. In certain further embodiments, for example, the volumes of the reaction vessels may range from 1 attoliter (or smaller) to 100 nanoliters (or larger). In certain further embodiments, for example, the volumes of the reaction vessels may be selected depending upon one or more of the nature of the capture objects, the detection technique and equipment employed, the number and density of the wells on the substrate, and the expected concentration of capture objects in the fluid applied to the substrate containing the wells. In certain embodiments, for example, the size of one or more of the reaction vessels may be selected such only a single capture object used for biomarker capture can be fully contained within the reaction vessel. In certain embodiments, for example, the size of one or more of the reaction vessels may be selected according to one or more of the embodiments disclosed in U.S. patent application Ser. No. 12/731,130, filed Mar. 24, 2010, published as US-2011-0212848 on Sep. 1, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al.; or International Patent Application No. PCT/US2011/026645, filed Mar. 1, 2011, published as WO 2011/109364 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al., each herein incorporated by reference.

In certain embodiments, for example, the reaction vessels may have a volume between about 1 femtoliter and about 1 picoliter, between about 1 femtoliters and about 100 femtoliters, between about 10 attoliters and about 100 picoliters, between about 1 picoliter and about 100 picoliters, between about 1 femtoliter and about 1 picoliter, or between about 30 femtoliters and about 60 femtoliters. In certain embodiments, for example, the reaction vessels have a volume of less than about 1 picoliter, less than about 500 femtoliters, less than about 100 femtoliters, less than about 50 femtoliters, or less than about 1 femtoliter. In certain embodiments, for example, the reaction vessels have a volume of about 10 femtoliters, about 20 femtoliters, about 30 femtoliters, about 40 femtoliters, about 50 femtoliters, about 60 femtoliters, about 70 femtoliters, about 80 femtoliters, about 90 femtoliters, or about 100 femtoliters.

In certain embodiments, for example, the total number of locations and/or density of the locations employed in an assay. In certain embodiments, for example, the total number of locations and/or density of the locations of reaction vessels in an array of reaction vessels can depend on the composition and end use of the array. In certain embodiments, for example, the number of reaction vessels employed may depend on the number of types of biomarker molecule and/or binding ligand employed, the suspected concentration range of the assay, the method of detection, the size of the capture objects, the type of detection entity (for example free labeling agent in solution, precipitating labeling agent, etc.). In certain embodiments, for example, arrays containing from about 2 to more than 1 billion reaction vessels (or total number of reaction vessels) may be made by utilizing any one of a variety of techniques and materials. In certain embodiments, for example, increasing the number of reaction vessels in the array may be used to increase the dynamic range of an assay or to allow multiple samples or multiple types of biomarker molecules to be assayed in parallel. In certain embodiments, for example, the array may comprise between one thousand and one million reaction vessels per sample to be analyzed. In certain embodiments, for example, the array may comprise greater than one million reaction vessels. In certain embodiments, for example, the array may comprise between about 1,000 and about 50,000, between about 1,000 and about 1,000,000, between about 1,000 and about 10,000, between about 10,000 and about 100,000, between about 100,000 and about 1,000,000, between about 100,000 and about 500,000, between about 1,000 and about 100,000, between about 50,000 and about 100,000, between about 20,000 and about 80,000, between about 30,000 and about 70,000, between about 40,000 and about 60,000 reaction vessels. In certain embodiments, for example, the array may comprise about 10,000, about 20,000, about 50,000, about 100,000, about 150,000, about 200,000, about 300,000, about 500,000, about 1,000,000, or more, reaction vessels.

In certain embodiments, for example, the array of reaction vessels may be arranged on a substantially planar surface or in a non-planar three-dimensional arrangement. In certain embodiments, for example, the reaction vessels may be arrayed in a regular pattern or may be randomly distributed. In certain embodiments, for example, the array may be a regular pattern of sites on a substantially planar surface permitting the sites to be addressed in an X-Y coordinate plane.

In certain embodiments, for example, the reaction vessels may be formed in a solid material. Suitable materials in which the reaction vessels can be formed includes, but is not limited to, glass (including modified and/or functionalized glass), plastics (including acrylics, polystyrene and copolymers of styrene and other materials, polypropylene, polyethylene, polybutylene, polyurethanes, cyclic olefin copolymer (COC), cyclic olefin polymer (COP), Teflon®, polysaccharides, nylon or nitrocellulose, etc.), elastomers (such as poly(dimethyl siloxane) and poly urethanes), composite materials, ceramics, silica or silica-based materials (including silicon and modified silicon), carbon, metals, optical fiber bundles, or the like. In certain embodiments, for example, the substrate material may be selected to allow for optical detection without appreciable autofluorescence. In certain embodiments, for example, the reaction vessels may be formed in a flexible material.

A reaction vessel in a surface (for example a substrate or a sealing component) may be formed using a variety of techniques known in the art, including, but not limited to, photolithography, stamping techniques, molding techniques, etching techniques, or the like. As will be appreciated by those of the ordinary skill in the art, the technique used can depend on the composition and shape of the supporting material and the size and number of reaction vessels. In a particular embodiment, an array of reaction vessels is formed by creating microwells on one end of a fiber optic bundle and utilizing a planar compliant surface as a sealing component.

In certain embodiments, for example, the methods and assays may be carried out using commercially available systems, for example, the Simoa HD-1 Analyzer and Quanterix SR-X (Quanterix™, Lexington, Mass.) and the systems described in U.S. patent application Ser. No. 13/035,472, filed Feb. 25, 2011, published as US 2012-0196774, entitled “SYSTEMS, DEVICES, AND METHODS FOR ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES,” by Fournier et al., herein incorporated by reference.

In certain embodiments, for example, the array of reaction vessels may be fabricated using other methods and materials that do not utilize the ends of an optical fiber bundle as a substrate. In certain embodiments, for example, the array may be a spotted, printed or photolithographically fabricated substrate produced by techniques known in the art such as those disclosed in WO95/25116; WO95/35505; PCT US98/09163; U.S. Pat. Nos. 5,700,637, 5,807,522, 5,445,934, 6,406,845, and 6,482,593, which are hereby incorporated, in their entirety, by reference. In certain embodiments, for example, the array may be produced using molding, embossing, and/or etching techniques as will be known to those of ordinary skill in the art.

In certain embodiments, for example, the plurality of locations may not comprise a plurality of reaction vessels/wells. In certain embodiments, for example, a patterned substantially planar surface may be employed and the patterned areas form a plurality of locations for receiving the capture objects. In certain embodiments, for example, the patterned areas may comprise substantially hydrophilic surfaces which are substantially surrounded by substantially hydrophobic surfaces. In certain embodiments, for example, a plurality of capture objects (for example beads) may be substantially surrounded by a substantially hydrophilic medium (for example comprising water), and the beads may be exposed to the patterned surface such that the beads associate in the patterned areas (for example the hydrophilic locations on the surface), thereby spatially segregating the plurality of beads. In certain embodiments, for example, a substrate may be or include a gel or other material able to provide a sufficient barrier to mass transport (for example convective and/or diffusional barrier) to prevent capture objects used for biomarker capture and/or precursor labeling agent and/or labeling agent from moving from one location on or in the material to another location so as to cause interference or cross-talk between spatial locations containing different capture objects during the time frame required to address the locations and complete the assay. In certain embodiments, for example, a plurality of capture objects may be spatially separated by dispersing the capture objects on and/or in a hydrogel material. In certain embodiments, for example, a precursor labeling agent may be already present in the hydrogel, thereby facilitating development of a local concentration of the labeling agent (for example upon exposure to a binding ligand or biomarker molecule carrying an enzymatic component). In certain embodiments, for example, the capture objects may be confined in one or more capillaries. In certain embodiments, for example, the plurality of capture objects may be absorbed or localized on a porous or fibrous substrate (for example filter paper). In certain embodiments, for example, the plurality of capture objects may be absorbed or localized on a substrate for obtaining and drying a capillary blood sample. In certain embodiments, for example, the capture objects may be spatially segregated on a uniform surface (for example a planar surface), and the capture objects may be detected using precursor labeling agents which are converted to substantially insoluble or precipitating labeling agents that remain localized at or near the location of where the corresponding capture object is localized. The use of such substantially insoluble or precipitating labeling agents is described herein. In certain embodiments, for example, single biomarker molecules may be spatially segregated into a plurality of droplets. In certain embodiments, for example, single biomarker molecules may be substantially contained in a droplet containing a first fluid. In certain embodiments, for example, the droplet may be substantially surrounded by a second fluid, wherein the second fluid is substantially immiscible with the first fluid.

Certain embodiments may provide, for example, methods and assays comprising at least one washing. In certain embodiments, for example, a wash solution for the washing is selected so that it does not cause appreciable change to the configuration of the capture objects. In certain embodiments, for example, a wash solution for the washing is selected so that it does not cause appreciable change to the biomarker molecules. In certain embodiments, for example, a wash solution for the washing is selected so that it does not disrupt any specific binding interaction between at least two components (for example between a capture component and a biomarker molecule component). In certain embodiments, for example, the wash solution may be a solution that is selected to chemically interact with one or more assay components. As will be understood by those of ordinary skill in the art, a wash step may be performed at any appropriate time point during the methods and assays. In certain embodiments, for example, a plurality of capture objects may be washed after exposing the capture objects to one or more solutions comprising biomarker molecules, binding ligands, precursor labeling agents, or the like. In certain embodiments, for example, following immobilization of the biomarker molecules with respect to a plurality of capture objects, the plurality of capture objects may be subjected to a washing step thereby removing any biomarker molecules not specifically immobilized with respect to a capture object.

Other assay methods in addition to those described herein are known in the art and may be used in connection with the inventive methods. In certain embodiments, for example, various analyzers are commercially available for the determination of the concentration of biomarkers. The assay methods employed should meet the algorithm requirements for LOD and LOQ.

INCORPORATION BY REFERENCE

Without limitation, the following documents are hereby incorporated, in their entirety, by reference: U.S. Patent Application Publication Nos. 2002/0122612, 2003/0016897, 2003/0027126, 2005/0130188, 2006/0013543, 2007/0040095, 2007/0122861, 2007/0259448, 2007/0259385, 2007/0259381, 2008/0032324, 2009/0101175, 2009/0149341, 2009/0156425, 2009/0170728, 2010/0075862, 2010/0075407, 2010/0075439, 2010/0075355, 2011/0195852, 2011/0212848, 2011/0212462, 2011/0212537, 2011/0245097, 2011/0251105, 2012/0135154, 2012/0196774, 2012/0277114, 2013/0034284, 2013/0142710, 2013/0266969, 2014/0094386, 2014/0134652, 2014/0227720, 2014/0302532, 2015/0038355, 2015/0353997, 2016/0123969, 2017/0160292, 2018/0003703, 2018/0037614, and 2018/0339296; U.S. Pat. No. 6,706,526; U.S. Provisional Application Nos. 62/655,738 and 62/789,067; International Patent Publication Nos. WO 2009/029073, WO 2010/039179, WO 2011/109364, WO 2011/109372, WO 2011/109379, WO 2016/115256, WO 2016/130923, and WO2018/222585; Kuhle, J. et al., “Comparison of three analytical platforms for quantification of the neurofilament light chain in blood samples: ELISA, electrochemiluminescence immunoassay and Simoa,” Clin Chem Lab Med 54:10 (2016) 1655-1661; Rissin, D. M. et al., “Simultaneous Detection of Single Molecules and Singulated Ensembles of Molecules Enables Immunoassays with Broad Dynamic Range,” Anal Chem 83:6 (2011) 2279-2285; Armbruster, D. A. et al., “Limit of Blank, Limit of Detection and Limit of Quantitation,”Clin Biochem Rev 29(Suppl 1) (2008) S49-S52; Quanterix, “Neuro 4-Plex A Kit: Material Safety Data Sheet,” (May 25, 2017), available at https://www.quanterix.com/sites/default/files/safety_data_sheets/Neuro%204-Plex%20A%20Kit%20102153.pdf; Harlow and Lane, (1988) Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, New York; Demidov, V. et al., “DNA Amplification: Current Technologies and Applications,” J Antimicrobial Chemotherapy 54:6 (2004); Depoorter et al., “Neurofilament Light Chain: Blood Biomarker of Neonatal Neuronal Injury” Front. Neurol. (20 Nov. 2018), available at https://www.frontiersin.org/articles/10.3389/fneur.2018.00984/full; Gill, J. et al., “Glial fibrillary acidic protein elevations relate to neuroimaging abnormalities after mild TBI,” Neurology 91:15 (Oct. 9, 2018) e1385-e1389; Korley, F. K., “Performance Evaluation of a Multiplex Assay for Simultaneous Detection of Four Clinically Relevant Traumatic Brain Injury Biomarkers,” J. Neurotrauma 36 (Jan. 1, 2019) 182-187; Hossain, I. et al., “Early Levels of Glial Fibrillary Acidic Protein and Neurofilament Light Protein in Predicting the Outcome of Mild Traumatic Brain Injury,” J. Neurotrauma 36 (2019) 1-10; Good, N. E. et al., “Hydrogen Ion Buffers for Biological Research,” Biochemistry 5:2 (1966) 467-477; Crowther, J R., “ELISA: Theory and Practice Methods,” Mol. Biol. 42 (1995) 1-218; Davies, C., “Concepts,” In the Immunoassay Handbook, D. Wild, ed., Stockton Press, New York (1994) 83-115; Hornbeck, P., “Enzyme-Linked Immunosorbent Assays,” In Current Protocols in Immunology, Unit 2.1, ed., R. Coico, John Wiley & Sons, Hoboken, N.J. (2001); and Pirkanniemi, K. “Complexing Agents Long-term Toxicity, Catalytic Oxidative Degradation and Concentrations in Industrial Waste Water,” Doctoral Dissertation, University of Kuopio (2007) (collectively, the “INCORPORATED REFERENCES”).

EXAMPLES

In the following Examples:

“AEB” means “average enzyme per bead”;

“>” means “greater than”;

“<” means “less than”;

“LOB” means “limit of blank”;

“LOD” means “limit of detection”;

“LOQ” means “limit of quantification”;

“q.s.” refers to a quantity of buffer sufficient to bring the listed components to the concentrations indicated;

“n.a.” means “not applicable”; and

“---” indicates no data presented.

“no.” means “number”;

“SD” means “standard deviation”;

“NSI” means “Neurobehavioral Symptom Inventory”;

“MVA” means “motor vehicle accident”;

“+” means positive indication of brain injury;

“−” means negative indication of brain injury;

“S” means “statistically significant difference”; and

“NS” means “nonsignificant difference”.

EXAMPLE 1 Multiplex Digital Assays of Dried Spots Whole Blood Preparation of Dried Blood Spots

Liquid human venous whole blood was collected from four individuals into EDTA collection tubes, and dried blood spots prepared by depositing 50 mcL per spot within 5 minutes of collection onto a series of Whatman® protein saver cards followed by drying in air at room temperature. Control blood spots were stored frozen at −80° C.

Simoa Multiplex Neurology 4-Plex “A” (N4PA) Assays

Dried blood spots were thawed at room temperature for 1 hour, eluted in 500 mcL N4PA kit sample diluent for 4 hours on an orbital shaker at 500 RPM at room temperature to provide liquid samples. The liquid samples were incubated at room temperature under rotation with assay kit capture beads for one hour, and concentrations of NF-L, Tau, GFAP, and UCH L1 measured using a Quanterix HD-1 Analyzer.

Results

Observed Concentration Ranges are Presented in Table 1.

TABLE 1 Concentration Ranges of Dried Blood Samples.^(1, 2) Concentration Range Analyte (pg/mL) N4PA LOQ NF-L 0.351-3.07  0.241 Tau 1.50-2.34 0.053 GFAP 1.70-3.90 0.467 UCH L1 45.5-130  5.45 ¹Reported as concentration in blood. ²Two blood spots were measured from each protein saver card. Coefficients of variation (CV) between the two spots' analyte concentrations were found to have CV's < 30%, with CV's < 20% for 81.25% of samples.

Two blood spots were immune-depleted and retested. Results are shown in Table 2.

TABLE 2 Immuno-depletion Results NF-L Concentration² Tau Concentration GFAP Concentration UCH L1 Concentration Sample¹ Before After Before After Before After Before After Dried Blood Spot 1 Unaged 1.94 <LOQ 1.94 0.55 1.50 <LOQ 44.47 39.80 21 Days Aged 2.16 <LOQ 2.73 0.49 1.08 <LOQ 36.56 82.94 Dried Blood Spot 2 Unaged 1.49 <LOQ 1.49 0.41 3.13 <LOQ 79.58 82.94 21 Days Aged 12.86 <LOQ 2.03 0.40 2.99 <LOQ 74.01 61.30 ¹Liquid samples from two dried blood spots were immuno-depleted with excess (10X) capture beads, and assayed using the Quanterix N4PA assay kit and the Simoa assay platform. Liquid samples were taken from unaged (i.e., maintained at −80° C. until tested) and aged blood spots (i.e., aged at room temperature) for the indicated number of days. ²Concentrations expressed as pg/mL.

Stability of analyte concentrations as a function of blood spot aging at room temperature is reported in FIGS. 4-7.

Example 2

The following non-limiting example describes a human multiplex assay that measured four important neurology biomarkers in both CSF and blood. The four targets were NF-L, total tau protein, GFAP, and UCH-L1. All four biomarkers have been studied as indicators of traumatic brain injury severity. Recent reports indicate serum NF-L is a biomarker for mild TBI in amateur boxers and professional hockey players1, that plasma tau is related to concussion severity, and that serum GFAP and UCH-L1 can detect mild to moderate TBI. The four targets were measured in a single performance of the assay. Each assay of the multiplex assay is described below.

NF-L is a 68 kDa cytoskeletal intermediate filament protein that is expressed in neurons. It associates with the 125 kDa Neurofilament medium(NF-M) and the 200 kDa Neurofilament heavy (NF-H) to form neurofilaments. They are major components of the neuronal cytoskeleton, and are believed to function primarily to provide structural support for the axon and to regulate axon diameter. Neurofilaments can be released in significant quantity following axonal damage or neuronal degeneration. NF-L has been shown to associate with traumatic brain injury, multiple sclerosis, frontotemporal dementia and other neurodegenerative diseases. The NF-L assay was a digital immunoassay for the quantitative determination of NF-L in serum, plasma and CSF. The antibodies also cross reacted with murine, bovine, and macaque NF-L epitopes, and the assay could be used for research with these species.

FIG. 8A shows the NF-L immunoassay dose-response curve. Calibrators were assayed in replicates of three. Four-parameter curve fit parameters are depicted. The analytical performance characteristics of the NF-L portion of the multiplex assay were characterized as summarized in Table 3 below. Table 4 shows the reproducibility of the NF-L immunoassay portion of the multiplex assay. FIG. 8B shows the NF-L concentration in EDTA plasma (n=20), matched serum (n=20) and CSF (n=20) from healthy donors. Error bars depict mean and interquartile ranges.

TABLE 4 Reproducibility precision of NF-L immunoassay across instruments and reagent lots. Reproducibility was determined with guidance from CLSI Protocol EP5-A. Five samples consisting of two serum panels, one plasma panel, and two NF-L controls were assayed in replicates of three for two runs on each of three instruments and two reagent lots. Analysis of variance (nested ANOVA) results are summarized in the following table. Between Mean NF-L Instrument Between Lot Between Run Within Run Sample pg/mL % CV, n = 3 % CV, n = 2 % CV, n = 12 % CV, n = 30 Control 1 9.31 0.9 3.4 5.8 6.2 Control 2 925 0.0 6.1 4.6 4.4 Serum Panel 1 16.8 0.0 0.0 5.1 5.4 Plasma Panel 2 60.1 0.0 0.0 5.6 4.7 Serum Panel 3 332 0.0 3.7 5.0 4.7

Tau is a microtubule-stabilizing protein primarily localized in CNS neurons, but also expressed at low levels in astrocytes and oligodendrocytes. Tau consists of six isoforms in the human brain, with molecular weights of 48,000 to 67,000 Daltons depending on isoform. Tau elevation is observed in the CSF of patients with neurodegenerative disease and head injuries, suggesting its extracellular release during neuronal damage and a role as a biomarker with specificity for brain injury. Potential movement of elevated CSF tau protein across the blood-brain barrier presents a possibility that measurements of tau protein in blood could provide a convenient peripheral window into brain/CSF status. Studies of tau protein in serum and plasma have been hampered by its low abundance (typically low pg/mL), and there are relatively few reports characterizing the appearance of tau protein in blood or evaluating the usefulness of this biomarker for brain injury assessment. Recent reports using digital immunoassay technology have shown elevation in peripheral tau protein associated with hypoxic brain injury, concussed hockey players, and repetitive minimal head injury in Olympic boxing. The total tau portion of the multiplex assay used a combination of monoclonal antibodies that react with both normal and phosphorylated tau. With an epitope in the midregion of the molecule, the assay recognizes all tau isoforms.

FIG. 9A shows the tau immunoassay dose-response curve. Calibrators were assayed in replicates of three. Four-parameter curve fit parameters are depicted. The analytical performance characteristics of the tau portion of the multiplex assay were characterized as summarized in Table 5 below. Table 6 shows the reproducibility of the NF-L immunoassay portion of the multiplex assay. FIG. 9B shows the tau concentration in EDTA plasma (n=20), matched serum (n=20) and CSF (n=20) from healthy donors. Error bars depict mean and interquartile ranges.

TABLE 6 Reproducibility precision of tau immunoassay across instruments and reagent lots. Reproducibility was determined with guidance from CLSI Protocol EP5-A. Five samples consisting of two serum panels, one plasma panel, and two tau controls were assayed in replicates of three for two runs on each of three instruments and two reagent lots. Analysis of variance (nested ANOVA) results are summarized in the following table. Between Between Between Within Mean Instrument Lot Run Run Tau % CV, % CV, % CV, % CV, Sample pg/mL n = 3 n = 2 n = 12 n = 30 Control 1 3.71 7.1 2.6 1.6 7.6 Control 2 200 0.0 6.7 4.5 4.5 Serum Panel 1 2.66 0.0 0.0 5.7 6.7 Plasma Panel 2 20.2 1.5 0.0 6.6 4.9 Serum Panel 3 148 5.2 0.0 3.0 5.2

GFAP is a class-III intermediate filament majorly expressed in astrocytic glial cells in the central nervous system. Astrocytes play a variety of key roles in supporting, guiding, nurturing, and signaling neuronal architecture and activity. Monomeric GFAP is about 55 kD. It is capable of forming both homodimers and heterodimers; GFAP can polymerize with other type III proteins or with neurofilament protein, such as NF-L. GFAP is involved in many important CNS processes, including cell communication and the functioning of the blood brain barrier. GFAP, as a potential biomarker has been shown to associate with multiple diseases such as traumatic brain injury, stroke, brain tumors, etc. Decreases in GFAP expression have been reported in Down's syndrome, schizophrenia, bipolar disorder, and depression.

FIG. 10A shows the tau immunoassay dose-response curve. Calibrators were assayed in replicates of three. Four-parameter curve fit parameters are depicted. The analytical performance characteristics of the GFAP portion of the multiplex assay were characterized as summarized in Table 7 below. Table 8 shows the reproducibility of the GFAP immunoassay portion of the multiplex assay. FIG. 10B shows the GFAP concentration in EDTA plasma (n=20), matched serum (n=20) and CSF (n=20) from healthy donors. Error bars depict mean and interquartile ranges.

TABLE 8 Reproducibility precision of GFAP immunoassay across instruments and reagent lots. Reproducibility was determined with guidance from CLSI Protocol EPS-A. Five samples consisting of two serum panels, one plasma panel, and two GFAP controls were assayed in replicates of three for two runs on each of three instruments and two reagent lots. Analysis of variance (nested ANOVA) results are summarized in the following table. Between Mean GFAP Instrument Between Lot Between Run Within Run Sample pg/mL % CV, n = 3 % CV, n = 2 % CV, n = 12 % CV, n = 30 Control 1 27.6 0.0 3.9 3.0 7.7 Control 2 1492 0.0 2.2 7.1 4.2 Serum Panel 1 59.4 0.0 8.5 3.8 3.9 Plasma Panel 2 226 0.0 3.0 6.2 3.6 Serum Panel 3 2095 0.0 6.5 3.8 4.5

UCH-L1 hydrolyzes small C-terminal adducts of ubiquitin to generate the ubiquitin monomer. It is also called PARK5 or neuronal-specific protein gene product 9.5, expressed predominantly in neurons, UCH-L1 is one of the most abundant brain protein, representing 1 to 2% of total soluble brain protein. In vivo, UCH-L1 has been shown to be involved in the regulation of the ubiquitin pool, apoptosis, learning and memory, and its absence in mice because of spontaneous intragenic deletions yields phenotypes with neurological defects. A point mutation (I93M) and a polymorphism (S18Y) in this gene have been shown to associate with Parkinson's disease. Recently, UCH-L1 has been proposed as a candidate biomarker for brain injury. UCH-L1 can be released from injured neurons and flow into the CSF and circulating blood.

FIG. 11A shows the tau immunoassay dose-response curve. Calibrators were assayed in replicates of three. Four-parameter curve fit parameters are depicted. The analytical performance characteristics of the UCH-L1 portion of the multiplex assay were characterized as summarized in Table 9 below. Table 10 shows the reproducibility of the UCH-L1 immunoassay portion of the multiplex assay. FIG. 11B shows the UCH-L1 concentration in EDTA plasma (n=20), matched serum (n=20) and CSF (n=20) from healthy donors. Error bars depict mean and interquartile ranges.

TABLE 10 Reproducibility precision of UCH-L1 immunoassay across instruments and reagent lots. Reproducibility was determined with guidance from CLSI Protocol EP5-A. Five samples consisting of two serum panels, one plasma panel, and two UCH-L1 controls were assayed in replicates of three for two runs on each of three instruments and two reagent lots. Analysis of variance (nested ANOVA) results are summarized in the following table. Between Mean UCH-L1 Instrument Between Lot Between Run Within Run Sample pg/mL % CV, n = 3 % CV, n = 2 % CV, n = 12 % CV, n = 30 Control 1 129 1.8 0.0 2.9 9.3 Control 2 13145 0.0 2.8 4.9 5.4 Serum Panel 1 71.9 5.0 0.0 6.4 11.3 Plasma Panel 2 381 4.8 0.0 4.9 5.6 Serum Panel 3 6663 0.0 4.2 5.9 4.2

Example 3

This example describes the materials and methods used in Example 3.

Instrumentation

The multiplex assay in Example 3 was formulated for use on either Quanterix Simoa HD-1 Analyzer or Simoa SR-X (Quanterix™, Lexington, Mass.). The Simoa HD-1 is a fully automated digital immunoassay analyzer that utilizes single molecule array (Simoa) technology for isolation and counting of single molecules. The instrument pipettes sample directly from sample tubes (capacity 96 tubes) and processes immunoassays and data reduction with a steady state throughput of 66 tests/hour. The Simoa SR-X is a semi-automated digital immunoassay detection system that functions like the HD-1 system except that samples and reagents are added manually to a 96-well ELISA plate for the assay-processing step. Following completion of the immunoassay processing, the ELISA plates are imaged automatically by the plate loading system, and processed in similar fashion to the HD-1. The multiplex assay in Example 3 was run on Simoa SR-X.

Reagents

The following four reagents were developed: paramagnetic capture beads, biotinylated detector molecules, streptavidin: β-galactosidase (SβG) conjugate, and sample diluent. The capture beads comprised a mixture of paramagnetic microbeads conjugated separately with anti-NF-L mouse monoclonal antibodies, anti-tau mouse monoclonal antibodies, anti-GFAP mouse monoclonal antibodies, and anti-UCH-L1 mouse monoclonal antibodies. For multiplexing, the beads were pre-coated with four separate fluorescent dyes, one dye for each analyte. Each fluorescently labeled bead type was assigned to one particular analyte (488 nm dye to NF-L, 750 nm dye to tau, 647 nm dye GFAP, and 700 nm dye to UCH-L1. The beads were not co-coated with all four antibodies, but were coated separately in independent batches, then mixed together in equal portions. The antibodies were covalently attached to the beads by standard carbodiimide coupling chemistry to 2.7-μm carboxy paramagnetic microbeads (Agilent Technologies). The antibody-coated beads were diluted to a concentration of 7×106 beads/mL in a diluent composed of 50 mM Tris (pH 7.8), 50 mM NaCl, 10 mM EDTA, 1% BSA, 0.1% Tween 20, and an antimicrobial preservative (ProClin 300). Biotinylated detector reagent comprised a mixture of four biotinylated mouse monoclonal antibodies directed to epitopes on NF-L, tau, GFAP, and UCH-L1. The antibodies were separately biotinylated using standard methods known in the art (e.g., EZ-Link NHS-PEG4-Biotin, Life Technologies), prior to mixing. Antibodies were diluted in such a way as to maximize signal while minimizing non-specific binding. Detector concentrations for the 4-plex differed significantly from what was utilized for single assays, and the range of detector concentrations was 0.1 μg/mL (NF-L) to 1.8 μg/mL (tau). Dilutions were performed in a diluent of phosphate-buffered saline (pH 7.4), 2% BSA, 0.1% Tween 20 and an anti-microbial preservative. SβG reagent was prepared by covalent conjugation of purified streptavidin (Thermo Scientific) and βG (Sigma) using standard coupling chemistry and diluted to 150 pM in phosphate buffered saline (pH 7.4) with 1% sucrose, 3% BSA, 0.1% Tween 20, and 1 mM MgCl₂ with an anti-microbial preservative. Sample diluent was formulated in phosphate buffered saline (pH 7.4) with dextrose (0.06%), BSA (0.02%), BGG (0.01%), urea (5 mM), Triton X-100 (0.5%), TRU block (10 mcg/mL), Superchemiblock (0.05%), and an anti-microbial preservative. This unique and complex formulation resulted in good analytical characteristics for the multiplex assay.

Calibration

Multi-constituent calibrators were prepared in a diluent of phosphate buffered saline, pH 7.4, with 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 μg/mL TRU block, 5 mM EDTA, and an anti-microbial (ProClin 300). The following antigens used were:

NF-light: Encor, recombinant human full length NF-L, Vendor Part #Prot-r-NF-L

Tau: Millipore Tau 381 (AG952)

GFAP: Hytest, native human GFAP, Vendor Part #8GF23

UCH-L1: Origene, recombinant human UCHL1, Vendor Part #TP301803. As described in the next section, the choice of GFAP antigen was important in reducing cross reactivity with the other three assays. Calibrator levels were:

NF-light: 0, 0.5, 1.5, 5, 15, 50, 150, 500 pg/mL,

Tau: 0, 0.1, 0.3, 1, 3, 10, 30, 100 pg/mL;

GFAP: 0, 1, 3, 10, 30, 100, 300, 1000 pg/mL;

UCH-L1: 0. 10, 30, 100, 300, 1000, 3000, 10000 pg/mL.

Protocol

The multiplex assay in Example 3 was a 2-step digital immunoassay. In the first step, assay specific antibody coated paramagnetic capture beads, sample, and biotinylated detector antibody were combined. These beads were labeled with different dyes. NF-L, tau, GFAP, and UCH-L1 molecules present in the sample were captured by the correspondent antibody coated capture beads and labeled with biotinylated detector antibodies. After washing, a conjugate of streptavidin-β-galactosidase (SBG) is mixed with the capture beads. SBG binds to the biotinylated detector antibodies, resulting in enzyme labeling of captured targets. Following a second wash, the capture beads are resuspended in a resorufin β-D-galactopyranoside (RGP) substrate solution and transferred to the Simoa Disc. Individual capture beads are then sealed within microwells in the array. If target has been captured and labeled, the β-galactosidase hydrolyzes the RGP substrate into a fluorescent product that provides the signal for measurement. A single labeled target molecule results in sufficient fluorescent signal to be detected and counted by the Simoa optical system. The dye signal on each bead is decoded to determine which target it captured. At low target concentration, the percentage of bead-containing wells in the array that have a positive signal is proportional to the amount of target present in the sample. At higher target concentration, when most of the bead-containing wells have one or more labeled target molecules, the total fluorescence signal is proportional to the amount of target present in the sample. The concentration of NF-L, Tau, GFAP, and UCH-L1 in unknown samples is interpolated from a standard curve.

When running the described reagents for the 4-plex on the HD-1, the above protocol was executed automatically by the instrument. When utilizing the SR-X instrument, the above protocol was performed outside of the instrument with manual pipetting by the user. The following sequence of steps were used to perform the testing manually in preparation for detection with the SR-X system. First, sample dilutions were prepared were diluted 4× in sample diluent. Then, aliquots of diluted samples were pipetted into ELISA plate wells. Third, capture beads were pipetted into each ELISA plate well (20 μl per well). Next, detector molecules were pipetted into each ELISA well (20 μl per well). Then, the sample plate was incubated on a microplate shaker for 30 minutes, 800 rpm, 30° C. Next, the sample plate was washed using a microplate washer (e.g., BioTek washer) with 3 cycles with Tris wash buffer. The total wash time was 5 minutes. Then SBG reagent was added (100 μl per well). Next, a second wash was performed using a microplate washer (e.g., BioTek washer) with 2 cycles with sucrose-containing wash buffer. The total wash time was 2 minutes. Then, the plate was incubated on magnet for 10 minutes to dry pellet. Once, the assay prep was complete, the plate was transferred to SR-X and start run.

Example 4

The following non-limiting example describes the non-specific binding of certain GFAP antigen used for calibration. Table A shows the average enzyme per bead (AEB) and the S/B for a calibration curve using GFAP Vendor An antigen and GFAP Hytest antigen.

TABLE A Antigen GFAP Vendor A Beads Tau Ab42 GFAP UCHL1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.035 0.020 0.012 0.007 Cal B 0.122 0.033 1.0 0.025 1.3 0.019 1.6 0.009 1.2 Cal C 0.488 0.034 1.0 0.028 1.4 0.046 3.9 0.011 1.6 Cal D 1.95 0.051 1.5 0.029 1.5 0.138 11.8 0.014 2.0 Cal E 7.81 0.112 3.2 0.039 2.0 0.121 10.3 0.037 5.3 Cal F 31.3 0.339 9.7 0.103 5.3 1.938 165.1 0.101 14.2 Cal G 125 1.079 31.0 0.221 11.3 7.245 617.2 0.406 57.0 Cal H 500 3.132 89.9 0.667 34.0 21.285 1813.1 1.594 223.7 Antigen GFAP Hytest vendor Beads Tau Ab42 GFAP UCH L1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.015 0.025 0.008 0.008 Cal B 0.122 0.020 1.3 0.024 0.9 0.020 2.5 0.013 1.5 Cal C 0.488 0.021 1.4 0.024 0.9 0.034 4.2 0.010 1.2 Cal D 1.95 0.022 1.5 0.026 1.0 0.076 9.4 0.011 1.3 Cal E 7.81 0.020 1.3 0.024 0.9 0.281 34.4 0.012 1.5 Cal F 31.3 0.015 1.0 0.025 1.0 1.123 137.6 0.012 1.5 Cal G 125 0.020 1.3 0.025 1.0 4.672 572.7 0.012 1.5 Cal H 500 0.023 1.5 0.032 1.3 14.939 1831.5 0.013 1.6

Example 5

The following non-limiting example describes the cross-reactivity and/or non-specific binding of certain UCH-L1 clones with NF-L capture beads. UCH-L1 clones 2D3 and 1016 produced a relatively high non-specific binding signal and were incompatible with the multiplex format as shown in Table B-1. Conversely, UCH-L1 clones 10D1 and 1033 did not produce a detectable non-specific signal as shown in Table B2.

TABLE B-1 UCHL1 antibody pair 2D3-1016 causing crosstalk Antigen Tau Antigen NF-L Beads Tau NF-L Beads Tau NF-L Detector Det Mix Det Mix Detector Det Mix DetMix Calibrator pg/mL AE8 S/B AEB S/B Calibrator pg/mL AEB S/B AE8 S/B Cal A 0 0.031 0.400 Cal A 0 0.034 0.548 Cal B 0.024 0.039 1.3 0.436 1.1 Cal B 0.014 0.037 1.1 0.522 1.0 Cal C 0.098 0.051 1.7 0.444 1.1 Cal C 0.055 0.030 0.9 0.542 1.0 Cal D 0.391 0.106 3.5 0.418 1.0 Cal D 0.218 0.033 1.0 0.608 1.1 Cal E 1.56 0.302 9.8 0.449 1.1 Cal E 0.87 0.028 0.8 0.717 1.3 Cal F 6.25 0.461 15.0 0.461 1.2 Cal F 3.49 0.029 0.9 #DIV/0! #DIV/0! Cal G 25.0 2.882 93.9 0.489 1.2 Cal G 14.0 0.031 0.9 #DIV/0! #DIV/0! Cal H 100 9.314 303.3 0.587 1.5 Cal H 55.9 0.032 1.0 #DIV/0! #DIV/0! Antigen GFAP Vendor A Antigen UCHL1 Vendor B Beads Tau NF-L Beads Tau NF-L Detector Det Mix Det Mix Detector Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B Calibrator pg/mL AEB S/B AEB S/B Cal A 0 0.035 0.515 Cal A 0 0.029 0.516 Cal B 0.122 0.033 1.0 0.468 0.9 Cal B 1.22 0.032 1.1 0.539 1.0 Cal C 0.488 0.034 1.0 0.477 0.9 Cal C 4.88 0.033 1.2 0.511 1.0 Cal D 1.95 0.051 1.5 0.499 1.0 Cal D 19.5 0.034 1.2 0.494 1.0 Cal E 7.81 0.112 3.2 0.570 1.1 Cal E 78.1 0.035 1.2 0.515 1.0 Cal F 31.3 0.339 9.7 0.589 1.1 Cal F 313 0.032 1.1 0.433 0.8 Cal G 125 1.079 31.0 0.726 1.4 Cal G 1250 0.032 1.1 0.458 0.9 Cal H 500 3.132 89.9 #DIV/0! #DIV/0! Cal H 5000 0.041 1.4 0.471 0.9

TABLE B2 UCHL1 antibody pair 1001-1033 had minimal crosstalk Antigen Tau Beads Tau Ab42 GFAP UCHL1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.011 0.028 0.014 0.010 Cal B 0.024 0.013 1.2 0.028 1.0 0.015 1.0 0.011 1.1 Cal C 0.098 0.026 2.4 0.026 0.9 0.012 0.8 0.010 0.9 Cal D 0.391 0.050 4.7 0.026 0.9 0.013 0.9 0.014 1.3 Cal E 1.56 0.178 16.5 0.028 1.0 0.015 1.1 0.012 1.1 Cal F 6.25 0.673 62.7 0.025 0.9 0.017 1.2 0.018 1.7 Cal G 25.0 2.184 203.6 0.031 1.1 0.030 2.1 0.036 3.5 Cal H 100 8.638 805.0 0.037 1.3 0.076 5.3 0.109 10.5 Antigen Ab42 Beads Tau Ab42 GFAP UCHL1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.015 0.029 0.012 0.010 Cal B 0.014 0.012 0.8 0.029 1.0 0.013 1.0 0.015 1.4 Cal C 0.055 0.016 1.1 0.051 1.8 0.014 1.1 0.012 1.1 Cal D 0.218 0.012 0.8 0.104 3.6 0.014 1.2 0.014 1.4 Cal E 0.87 0.017 1.1 0.310 10.7 0.012 1.0 0.011 1.1 Cal F 3.49 0.015 1.0 1.187 40.8 0.014 1.1 0.013 1.3 Cal G 14.0 0.014 1.0 3.648 125.5 0.014 1.1 0.014 1.3 Cal H 56 0.017 1.2 14.216 489.1 0.013 1.1 0.013 1.3 Antigen UCHL Beads Tau Ab42 GFAP UCHL1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.029 0.029 0.014 0.013 Cal B 1.22 0.032 1.1 0.033 1.1 0.014 1.0 0.018 1.4 Cal C 4.88 0.033 1.2 0.030 1.0 0.016 1.1 0.025 2.0 Cal D 19.5 0.034 1.2 0.030 1.0 0.014 1.0 0.056 4.4 Cal E 78.1 0.035 1.2 0.031 1.1 0.014 1.0 0.182 14.5 Cal F 313 0.032 1.1 0.032 1.1 0.016 1.1 0.638 50.8 Cal G 1250 0.032 1.1 0.032 1.1 0.022 1.6 2.051 163.1 Cal H 5000 0.041 1.4 0.040 1.4 0.039 2.7 9.591 762.7 Antigen GFAP Beads Tau Ab42 GFAP UCHL1 Detector Det Mix Det Mix Det Mix Det Mix Calibrator pg/mL AEB S/B AEB S/B AEB S/B AEB S/B Cal A 0 0.015 0.025 0.008 0.008 Cal B 0.122 0.020 1.3 0.024 0.9 0.020 2.5 0.013 1.5 Cal C 0.488 0.021 1.4 0.024 0.9 0.034 4.2 0.010 1.2 Cal D 1.95 0.022 1.5 0.026 1.0 0.076 9.4 0.011 1.3 Cal E 7.81 0.020 1.3 0.024 0.9 0.281 34.4 0.012 1.5 Cal F 31.3 0.015 1.0 0.025 1.0 1.123 137.6 0.012 1.5 Cal G 125 0.020 1.3 0.025 1.0 4.672 572.7 0.012 1.5 Cal H 500 0.023 1.5 0.032 1.3 14.939 1831.5 0.013 1.6

Example 6

The following non-limiting example describes the use of certain detergents in the sample diluent. Triton X100 was found to be suitable for both Tau and UCH-L1 assays as shown in Table C.

TABLE C UCHL1 CSF Tau Normalized by Zero UCHL1 Normal cone Tau sample Sample Diluent Detergent signal sample signal (pg/mL) diluent Sample diluent 1 1% 3-(Decyldimethyl) 0.0030 0.0188 2.58  2% Sample diluent 2 1% N-Dodecyl 0.0038 84.37 50% Sample diluent 3 0.5% 3-(Decyldimethyl) 0.0060 20.75 12% Sample diluent 4 0.5% N-Dodecyl 0.0043 83.84 50% Sample diluent 5 0.5% Triton 0.0069 160.10 95% Sample diluent 6 0.5% Tw20 0.0078 147.59 88% Sample diluent 7 0.5% ASB14 0.0033 160.43 95% Tau sample diluent   1% ASB14 0.0029 168.10 100% 

Example 7

The following non-limiting example describes the use of blockers in the sample diluent to impart dilution linearity and predictable spike recovery. Superchemiblock produced linear dilutions and predictable spike recovery as shown in Table D.

TABLE D NF-L Buffer Corrected Recovery Sample ID Spiking Level w/o Superchemiblock w Superchemiblock Buffer  10 pg/mL 100%  100% 100 pg/mL 100%  100% Serum 1  10 pg/mL 43%  76% 100 pg/mL 34%  74% Serum 2  10 pg/mL 61%  92% 100 pg/mL 52% 104% Average 48%  87% NF-L Spiked Serum Dilution Linearity Dilution w/o Superchemiblock w Superchemiblock 1:4 100% 100% 1:8 106%  96%  1:16 139% 112%  1:32 156% 117%  1:64 181% 116%  1:128 212%  99% Average 159% 108% NF-L Endogenous CSF Dilution Linearity Dilution w/o Superchemiblock w Superchemiblock 1:4  100% 100% 1:8  102% 123% 1:16 112% 115% 1:32 129% 113% 1:64 143% 104%  1:128 192% 119%  1:256 301% 127%  1:512 602% 108% Average 210% 114% Tau Spiked Serum Dilution Linearity Dilution w/o Superchemiblock w Superchemiblock 1:4  100% 100%  1:8  100% 96% 1:16 115% 89% 1:32 152% 82% 1:64 171% 82%  1:128 186% 88%  1:256 217% 82%  1:512 236% 102%  Average 160% 90%

Example 8

The following non-limiting example describes the effect of detection molecule concentration on non-specific binding. Table E shows AEB and S/B for NF-L for different concentrations of UCH-L1 detector. The concentration of UCH-L1 detection molecules used in a single assay (i.e., 5 μg/mL) and the concentration used in the multiplex assay (i.e., 0.5 μg/mL) were investigated.

TABLE E Plex 4-plex-NFL [UCHL1 Det] 5 ug/mL 0.5 ug/mL Calibrator pg/mL AEB S/B AEB S/B Cal A 0 0.014 0.008 Cal B 1 0.017 1.3 0.016 1.9 Cal C 5 0.108 7.8 0.100 12.0 Cal D 50 0.864 62.4 0.884 106.1 Cal E 500 9.213 664.8 8.874 1065.0

For description of various details associate with this assay, see, for example, U.S. patent application Ser. No. 12/731,130, filed Mar. 24, 2010, published as US-2011-0212848 on Sep. 1, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al.; International Patent Application No. PCT/US2011/026645, filed Mar. 1, 2011, published as WO 2011/109364 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES USING BEADS OR OTHER CAPTURE OBJECTS,” by Duffy et al.; International Patent Application No. PCT/US2011/026657, filed Mar. 1, 2011, published as WO 2011/109372 on Sep. 9, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES USING DUAL DETECTION METHODS,” by Duffy et al.; U.S. patent application Ser. No. 12/731,135, filed Mar. 24, 2010, published as US-2011-0212462 on Sep. 1, 2011, entitled “ULTRA-SENSITIVE DETECTION OF MOLECULES USING DUAL DETECTION METHODS,” by Duffy et al.; International Patent Application No. PCT/US2011/026665, filed Mar. 1, 2011, published as WO 2011/109379 on Sep. 9, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Rissin et al.; U.S. patent application Ser. No. 12/731,136, filed Mar. 24, 2010, published as US-2011-0212537 on Sep. 1, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Duffy et al.; U.S. patent application Ser. No. 13/035,472, filed Feb. 25, 2011, published as US 2012-0196774, entitled “SYSTEMS, DEVICES, AND METHODS FOR ULTRA-SENSITIVE DETECTION OF MOLECULES OR PARTICLES,” by Fournier et al.; U.S. patent application Ser. No. 13/037,987, filed Mar. 1, 2011, published as US-2011-0245097 on Oct. 6, 2011, entitled “METHODS AND SYSTEMS FOR EXTENDING DYNAMIC RANGE IN ASSAYS FOR THE DETECTION OF MOLECULES OR PARTICLES,” by Rissin et al.; each herein incorporated by reference.

PROPHETIC EXAMPLES Prophetic Examples 9-10

NF-L assay calibration experiments. A series of calibration solutions with and without added non-analyte proteins would be assayed for NF-L in accordance with Table 11 and the results shown in Table 12 would be obtained.

TABLE 11 NF-L Assay Calibration Examples Non-Analyte Protein Added to Prophetic Example Assay Method Calibration Solutions³ Example 9 Digital assay¹ n.a. Example 10 Digital assay¹ 10 mcg/mL Comparative Example A Plate ELISA assay² n.a. Comparative Example B Plate ELISA assay² 10 mcg/mL ¹Carboxy-terminated, 2.7 micron-diameter magnetic beads (Agilent Technologies) would be prepared by conjugating with anti-NF-L mouse monoclonal antibodies (via carbodiimide coupling) and blocking. Antibody-coated beads would be diluted in a buffer solution. 100 mcL calibration solution would be mixed with a volume of the bead solution to provide 10⁹ beads and incubated, the beads washed post-incubation, resuspended and incubated with biotinylated detector reagent (mouse monoclonal anti-NF-L antibodies), washed, resuspended and incubated with streptavidin-β-galactosidase, loaded into microwell arrays, and NF-L quantified (average enzyme per bead (AEB) determined) using a Quanterix Simoa HD-1 Analyzer (Quanterix ™, Lexington, Massachusetts). ²Assay plates sold under the trademark Nunc 96 well Maxisorp ™ plates would be prepared by passively coating with anti-NF-L mouse monoclonal antibodies and blocking. Calibration solution would be mixed with biotinylated detector reagent (mouse monoclonal anti-NF-L antibodies), incubated in the plate, the plate washed post-incubation, streptavidin-β-galactosidase added, and NF-L quantified in a plate reader in chemiluminescent mode. ³Calibration solutions would be prepared by diluting 2000 pg/mL NF-L spike solution in NF-L calibration diluent. The NF-L calibration diluent would consist of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block ™, 0.05% ProClin ™ 300, and 5 mM EDTA.

TABLE 12 NF-L Assay Calibration Results Calibration Comparative Comparative Solution¹ Example 9 Example A Example 10 Example B 0   LOB   LOB   LOB   LOB 0.5 >LOQ >LOD >LOQ <LOD <LOQ 1.5 >LOQ >LOD >LOQ <LOD <LOQ 5 >LOQ >LOD >LOQ <LOD <LOQ 15 >LOQ >LOD >LOQ >LOD <LOQ <LOQ 50 >LOQ >LOD >LOQ >LOD <LOQ <LOQ 150 >LOQ >LOD >LOQ >LOD <LOQ <LOQ 450 >LOQ >LOD >LOQ >LOD <LOQ <LOQ ¹Calibration solution consisting of NF-L at the indicated concentration (pg/mL), 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block ™, 0.05% ProClin ™ 300, and 5 mM EDTA.

Calibration curves for the Examples would be obtained to express the concentration of NF-L (pg/mL) as a function of AEB by third-order polynomial fitted to the AEB data.

Prophetic Examples 11-15

Human fluid assays for NF-L. A series of digital assays would be conducted on various types of human fluid samples and AEB's obtained using a Quanterix Simoa HD-1 Analyzer (Quanterix™, Lexington, Mass.). NF-L concentrations would be obtained for the samples using the calibration curves noted and the results reported in Table 13 would be obtained.

TABLE 13 NF-L Assay Result¹ Capillary Capillary Venous Venous Prophetic blood blood blood blood Cerebrospinal Example Donor serum² supernatant³ serum² supernatant³ fluid² Example 11 Child A neonatal⁴ >LOQ >LOQ >LOQ >LOQ >LOQ Example 12 Child A newborn⁵ >LOQ >LOQ >LOQ >LOQ >LOQ Example 13 Adult Boxer X pre-fight >LOQ >LOQ >LOQ >LOQ >LOQ Example 14 Adult Boxer X post-fight⁶ >LOQ >LOQ >LOQ >LOQ >LOQ Example 15 Healthy Adult >LOQ >LOQ >LOQ >LOQ >LOQ ¹NF-L concentrations (pg/mL) would be obtained for diluted capillary blood serum and supernatant (obtained from dried capillary blood), for venous blood serum, supernatant obtained from dried venous blood, and CSF using the calibration curve obtained for Example 9. ²Samples would be diluted 128-fold in the NF-L calibration diluent. ³Samples would be provided as dried blood spots on filter paper, eluted in 10:90 vol/vol methanol/water mixture, dried under nitrogen, and reconstituted in water, centrifuged, and supernatant diluted 128-fold in sample diluent consisting of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, and 0.05% ProClin 300 ™ at pH 7.4. ⁴Sample obtained within 1 hour of birth. ⁵Sample obtained 1 month after birth. ⁶Sample obtained within 1 hour of fight.

Prophetic Examples 16-25

Assays for NF-L and Reference Marker obtained from dried capillary blood samples. A series of digital assays would be conducted on samples obtained from dried capillary blood spots and AEB's obtained using a Quanterix Simoa HD-1 Analyzer (Quanterix™, Lexington, Mass.). NF-L concentrations would be obtained for the samples using the calibration curves noted and the results reported in Table 14 would be obtained.

TABLE 14 NF-L and Reference Marker Assay Results¹⁻² Prophetic Ratio (w/w) Reference NF-L:Reference Example Donor Sample timing NF-L Biomarker Biomarker Example 16 Adult Boxer X 1 hour pre-fight >LOQ >LOQ As computed Example 17 Adult Boxer X 1 hour post-fight >LOQ >LOQ As computed Example 18 Adult Boxer X 8 hour post-fight >LOQ >LOQ As computed Example 19 Adult Boxer X 1 day post-fight >LOQ >LOQ As computed Example 20 Adult Boxer X 1 week post-fight >LOQ >LOQ As computed Example 21 Adult Boxer X 1 month post-fight >LOQ >LOQ As computed Example 22 Healthy Adult Donor A Initial time >LOQ >LOQ As computed Example 23 Healthy Adult Donor A Initial time + 1 day >LOQ >LOQ As computed Example 24 Healthy Adult Donor A Initial time + 1 week >LOQ >LOQ As computed Example 25 Healthy Adult Donor A Initial time + 1 month >LOQ >LOQ As computed ¹Samples would be provided as dried blood spots on filter paper, eluted in 10:90 vol/vol methanol/water mixture, dried under nitrogen, and reconstituted in water, centrifuged, and supernatant diluted 128-fold in sample diluent. ²NF-L concentrations (pg/mL) would be obtained for dried capillary blood supernatant using the calibration curve obtained for Example 9.

Prophetic Examples 26-27

Multiplex assay calibration experiments. A series of calibration solutions with and without added non-analyte proteins would be assayed for the following biomarkers: NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE, in accordance with Table 15 and the results reported in Table 16 would be obtained.

TABLE 15 Multiplex Digital Assay¹ Calibration Examples Non-Analyte Protein Added Prophetic Example to Calibration Solutions² Example 26 n.a. Example 27 10 mcg/mL ¹Separate portions of carboxy-terminated, 2.7 micron-diameter magnetic beads (Agilent Technologies) would be prepared by conjugating with anti-NF-L mouse monoclonal antibodies, anti-GFAP mouse monoclonal antibodies, anti-UCH L1 mouse monoclonal antibodies, anti-tau protein mouse monoclonal antibodies, anti-A beta 42/40 mouse monoclonal antibodies, anti-S100B mouse monoclonal antibodies, and anti-NSE mouse monoclonal antibodies (via carbodiimide coupling), blocking, and mixing the magnetic beads together. The mixed antibody-coated beads would be diluted in a buffer solution. 100 mcL calibration solution would be mixed with a volume of the bead solution to provide 10⁹ beads and incubated, the beads washed post-incubation, resuspended and incubated with biotinylated detector reagent, washed, resuspended and incubated with streptavidin-β-galactosidase, loaded into microwell arrays, and NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE quantified using a Quanterix Simoa HD-1 Analyzer (Quanterix ™, Lexington, Massachusetts). ²Calibration solutions would be prepared by diluting spike solution in calibration diluent. The calibration diluent would consist of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block ™, 0.05% ProClin ™ 300, and 5 mM EDTA.

TABLE 16 Biomarker Assay Calibration Results Calibration Solution¹ UCH A beta A beta Example Example NF-L GFAP L1 Tau 40 42 S100B NSE 26² 27³ 0 0 0 0 0 0 0 0 LOB LOB 0.5 1 10 0.1 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 1.5 3 30 0.3 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 5 10 100 1 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 15 30 300 3 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 50 100 1000 10 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 150 300 3000 30 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ 450 900 9000 90 0-250 0-250 0-10,000 0-10,000 >LOQ >LOQ ¹Calibration solution at indicated concentrations of NF-L, GFAP, UCH L1, Tau, A beta 40, S100B, and NSE (pg/mL), 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2% BSA, 0.1% 10G Surfactant, 10 mcg/mL TRU block ™, 0.05% ProClin ™ 300, and 5 mM EDTA. ²⁻³The indicated values would be obtained for each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE.

Calibration curves for the Examples would be obtained to express the biomarker concentrations (pg/mL) as a function of AEB by third-order polynomial fitted to the AEB data.

Prophetic Examples 28-32

Human fluid assays for NF-L. A series of digital assays would be conducted on various human fluid samples and AEB's obtained for NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE using a Quanterix Simoa HD-1 Analyzer (Quanterix™, Lexington, Mass.). Concentrations would be obtained for the samples using the calibration curves noted and results reported in Table 17 would be attained.

TABLE 17 Multiplex Assay Results For Each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE ¹ Prophetic Capillary Venous Example Donor blood² blood³ Example 28 Child A neonatal⁴ >LOQ >LOQ Example 29 Child A newborn⁵ >LOQ >LOQ Example 30 Adult Boxer X pre-fight >LOQ >LOQ Example 31 Adult Boxer X post-fight⁶ >LOQ >LOQ Example 32 Healthy Adult >LOQ >LOQ ¹ NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE concentrations (pg/mL) would be obtained for supernatant (obtained from dried capillary blood) and for venous blood serum using the calibration curve obtained for Example 26. ²Samples would be provided as dried blood spots on filter paper, eluted in 10:90 vol/vol methanol/water mixture, dried under nitrogen, and reconstituted in water, centrifuged, and supernatant diluted 128-fold in sample diluent consisting of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, and 0.05% ProClin ™ 300 at pH 7.4. ³Samples would be diluted 128-fold in sample diluent. ⁴Sample obtained within 1 hour of birth. ⁵Sample obtained 1 month after birth. ⁶Sample obtained within 1 hour of fight.

Prophetic Examples 33-41

Assays for NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, NSE and Reference Marker obtained from dried capillary blood samples. A series of multiplex digital assays would be conducted on samples obtained from dried capillary blood spots and AEB's obtained using a Quanterix Simoa HD-1 Analyzer (Quanterix™, Lexington, Mass.). Biomarker concentrations would be obtained for the samples using the calibration curves noted and results reported in Table 18 would be attained and compared to Reference Marker concentrations.

TABLE 18 Biomarker and Reference Marker (R) Multiplex Assay Results¹⁻² Assay result for each of NF-L, GFAP, UCH L1, Tau, A beta, Prophetic Sample S100B, Reference Example Donor timing and NSE Biomarker Example 33 Adult Boxer X 1 hour >LOQ >LOQ pre-fight Example 34 Adult Boxer X 1 hour >LOQ >LOQ post-fight Example 35 Adult Boxer X 1 day >LOQ >LOQ post-fight Example 36 Adult Boxer X 1 week >LOQ >LOQ post-fight Example 37 Adult Boxer X 1 month >LOQ >LOQ post-fight Example 38 Healthy Adult Initial time >LOQ >LOQ Donor A Example 39 Healthy Adult Initial time + >LOQ >LOQ Donor A 1 day Example 40 Healthy Adult Initial time + >LOQ >LOQ Donor A 1 week Example 41 Healthy Adult Initial time + >LOQ >LOQ Donor A 1 month ¹Samples would be provided as dried blood spots on filter paper, eluted in 10:90 vol/vol methanol/water mixture, dried under nitrogen, and reconstituted in water, centrifuged, and supernatant diluted 128-fold in sample diluent consisting of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, and 0.05% ProClin ™ 300. ²Analyte concentrations (pg/mL) would be obtained for dried capillary blood supernatant using the calibration curve obtained for Example 26.

Prophetic Examples 42-59

Assays for NF-L, GFAP, UCH L1, Tau, A beta, S100B, NSE and Reference Marker Persistence in Aged Capillary Blood Spots. A series of multiplex digital assays would be conducted on samples stored at the temperatures and for the times indicated in Table 19. The assays would be performed and AEB's obtained using a Quanterix Simoa HD-1 Analyzer (Quanterix™, Lexington, Mass.), and concentrations would be obtained from the AEB data using the calibration curves noted in Table 19.

TABLE 19 Biomarker and Sodium Persistence Results¹ Concentration of Each of NF-L, GFAP, UCH L1, Storage Elapsed Tau, A beta 40, Prophetic Temperature Time A beta 42, Sodium Example (° C.) (months) S100B, and NSE Concentration Example 42 −20 0 >LOQ >LOQ Example 43 3 >LOQ >LOQ Example 44 6 >LOQ >LOQ Example 45 12 >LOQ >LOQ Example 46 36 >LOQ >LOQ Example 47 60 >LOQ >LOQ Example 48 +4 −0 >LOQ >LOQ Example 49 3 >LOQ >LOQ Example 50 6 >LOQ >LOQ Example 51 12 >LOQ >LOQ Example 52 36 >LOQ >LOQ Example 53 60 >LOQ >LOQ Example 54 20 0 >LOQ >LOQ Example 55 3 >LOQ >LOQ Example 56 6 >LOQ >LOQ Example 57 12 >LOQ >LOQ Example 58 36 >LOQ >LOQ Example 59 60 >LOQ >LOQ ¹Samples would be provided as dried blood spots on filter paper, eluted in 10:90 vol/vol methanol/water mixture, dried under nitrogen, and reconstituted in water, centrifuged, and supernatant diluted 128-fold in sample diluent consisting of 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, and 0.05% ProClin ™ 300.

Prophetic Examples 60-62

Analysis of dried blood spot samples from patients with mild traumatic brain injury. A series of assay experiments for NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE would be performed on dried blood spot samples obtained from donors suspected for mild traumatic brain injury and from a control group. Donor characteristics that would be are shown in Table 20 and results that would be obtained are shown in Tables 21-22.

TABLE 20 Donor Characteristics in Examples 60-62 Injury Mechanisms Number Struck Prophetic of Demographic Characteristics² Vehicular by Example¹ Donors Age GCS NSI Male Accident Fall Assault Object Example 60 69 52.0 14.07 15.80 65% 40% 21% 17% 13% Example 61 28 46.0 14.42 14.89 60% 46% 32% 25%  7% Example 62 177 41.5 14.33 14.51 57% 54% 28% 18%  9% Comparative 49 48.6 n.a. n.a. 61% n.a. n.a. n.a. n.a. Example C ¹Donors in Examples 60-62 would be participants in a Traumatic Head Injury Neuroimaging Classification study. Samples would be provided as dried blood spots on filter paper, and eluted in sample diluent. Donors in Comparative Example C were healthy donors without a history of traumatic brain injury or neurologic disease. ²Mean age (“Age”), Glasgow Coma Scale (“GCS”), Neurobehavioral Symptom Inventory (“NSI”), and percentage male (“Male”) presented.

TABLE 21 Assay and Imaging Results Assay Results for Each of NF-L, GFAP, UCH L1, Imaging Prophetic Tau, A beta 40, A beta 42, Results² Example¹ S100B, and NSE ¹ MRI CT Example 60 >LOQ + + Example 61 >LOQ + — Example 62 >LOQ — — Comparative >LOQ n.a. n.a. Example C Statistical X² > 30, n.a. n.a. Significance³ p < 0.05 ¹ Analytes would be quantified by multiplex assay using a Simoa (Single Molecule Array) platform (Quanterix, Lexington, MA). Median and interquartile ranges would be presented in pg/mL ²MRI and CT would be performed within 48 hours of injury. MRI protocol would comprise diffusion-tensor imaging, T2*-weighted imaging, T2-fluid-attenuated inversion recovery (FLAIR), high-resolution 3D-T1, dynamic susceptibility contrast perfusion-weighted imaging, and post-contrast T1 and T2-FLAIR. ³Variances between the Examples and Comparative Example would be calculated using the Kruskal-Wallis and the Mann-Whitney tests, and correlation analyses would be performed using the Spearman rank test, with p-values adjusted for multiple comparisons with the Benjamini-Hochberg procedure. All tests would be 2-tailed; p < 0.05 would be considered significant.

TABLE 22 AUC's for Age-Adjusted ROC Curves in Examples 60-62 AUC of Each ROC Curve for NF-L, GFAP, Donors Used UCH L1, Tau, True True A beta 40, Negative Positive A beta 42, ROC Curve Condition Condition S100B, and NSE Healthy donors vs. donors Comparative Examples >0.6 suspected for mild Example C 60-62 traumatic brain injury (control vs. mTBI) Donors with positive vs. Examples Example >0.6 negative computed CT 61-62 60 indication of brain injury (CT⁺ vs. CT⁻) Donors with positive vs. Example 62 Examples >0.6 negative MRI indication 60-61 of brain injury (MRI⁺ vs. MRI⁻) Donors with negative Example 61 Example >0.6 CT and negative 60 MRI indication of brain injury vs. negative CT and positive MRI indications of brain injury (CT⁻ MRI⁻ vs. CT⁻ MRI⁺)

Prophetic Examples 63-64

Analysis of dried blood spot samples from patients with traumatic brain injury. A series of assay experiments for NF-L, Tau, GFAP, and UCH L1 would be performed on dried blood spot samples obtained from donors suspected for traumatic brain injury. Donor characteristics that would be obtained are shown in Table 23 and results that would be obtained are shown in Tables 24-25.

TABLE 23 Donor Characteristics in Examples 63-64 Injury Mechanisms Pedes- trian Vehic- Vehic- Number Demographic Characteristics² ular ular Struck Post-traumatic Amnesia Prophetic of GCS Acci- Acci- As- by Suspect- Un- example¹ Donors Age 3-8 9-12 13-15 Male dent dent Fall sault Object Yes ed No known Example 63 39.0   0% 1.6% 98.4% 63.5% 27.0% 6.3% 49.2% 12.7% 4.8% 55.6%  1.6% 33.3%  9.5% 63 Example 44 44.0 25.0% 9.1% 65.9% 86.4% 39.5% 2.3% 44.2% 14.0% 0.0% 43.2% 18.2% 18.2% 20.5% 64 ¹Donors in Examples 63-64 would be participants in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot (TRACK-TBIPilot Study). Samples would be provided as dried blood spots on filter paper, and eluted in sample diluent. ²Median age (“Age”), Glasgow Coma Scale (“GCS”), and percentage male (“Male”) presented.

TABLE 24 Assay and CT Scan Results Assay Results for Each of NF-L, Prophetic GFAP, UCH L1, Tau, A beta 40, example¹ A beta 42, S100B, and NSE ¹ CT² Example 63 >LOQ − Example 64 >LOQ + Statistical p < 0.001 n.a. Significance³ ¹ Analytes would be quantified in plasma samples by multiplex assay using the S.moa (Single Molecule Array) platform (Quanterix, Lexington, MA). Median and interquartile ranges would be presented in pg/mL. Digital assay results would be examined for normality with distributional plots and the Shapiro-Wilk test. ²Head CT would be performed within 24 hours of injury. ³The Mann-Whitney U test would be used to assess for between-group differences in the digital assay results.

TABLE 25 AUC's for Age-adjusted ROC Curves in Examples 63-64 AUC of Each Donors Used ROC Curve for NF-L, True True GFAP, UCH L1, Tau, Negative Positive A beta 40, A beta 42, ROC Curve Condition Condition S100B, and NSE Donors with normal Example 63 Examples 64 >0.6 vs. abnormal CT scans (CT⁻ vs. CT⁺)

Prophetic Examples 65-67

Analysis of dried blood spot samples from patients with RRMS. A series of digital assay experiments for NF-L, Tau, GFAP, and UCH L1 would be performed on dried blood spot samples obtained from donors diagnosed with RRMS. Results that would be obtained are shown in Table 26.

TABLE 26 Assay Results Assay Results for Each Relapsing- of NF-L, GFAP, remitting UCH L1, Tau, Multiple Prophetic Number of A beta 40, A beta 42, Sclerosis example¹ Donors S100B, and NSE² Severity³ Example 65 6 >LOQ Mild Example 66 6 >LOQ Moderate Example 67 4 >LOQ Severe Comparative 12 >LOQ n.a. Example D⁴ Statistical p < 0.001 p < 0.001 n.a. Significance⁵ ¹Samples would be provided as dried blood spots on filter paper, and eluted in the sample diluent. Samples from patients diagnosed with RRMS would be actively receiving medical treatment. ²Analytes would be quantified in plasma samples by multiplex assay using the Simoa (Single Molecule Array) platform (Quanterix, Lexington, MA). Mean concentration would be presented in pg/mL. ³RRMS severity would be categorized based on a physician's diagnosis. Mild: Expanded Disability Status Scale (EDSS) scores less than 3; moderate: EDSS scores between 3 and 5; severe: EDSS scores greater than 5. ⁴Donors in Comparative Example D would be healthy donors. ⁵The Mann-Whitney U test would be used to assess for between-group differences in the digital assay results.

Prophetic Examples 68-70

Prophetic assay analysis of dried blood spots samples diluted with sample diluent containing added human IgG. A series of assay experiments would be performed on dried blood spot samples at various levels of dilution and with and without added human IgG. Diluent compositions are shown in Table 27. The results shown in Tables 28-30 would be obtained.

TABLE 27 Diluent Compositions in Examples 68-70 Examples 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 68-70 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, 0.01% BgG, 5 mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, 5 mg/mL human IgG, and 0.05% ProClin 300 ™ at pH 7.4 Comparative 50 mM phosphate, 137 mM NaCl, 2.7 mM KCl, Examples 0.02% BSA, 1 mM MgCl₂, 0.06% dextrose, C-E 0.01% BgG, 5 mM urea, 0.5% Triton ™ X-100, 10 mcg/mL TRU block ™, 50 mcg/mL Superchemiblock ™, and 0.05% ProClin 300 ™ at pH 7.4

TABLE 28 Spike Recovery for Each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE¹ Spike Recovery for Each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, 5100B, and NSE Example 68 Comparative Example E 80-120% <70% 80-120% <70% 80-120% <70% 80-120% <70% 80-120% <70% 80-120% <70% ¹Samples would be spiked with 100 pg/mL each of GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE. Spike recovery is the ratio of observed concentration following subtraction of endogenous NF-L to expected concentration expressed as a percentage.

TABLE 29 Ratio of Concentration of Indicated Analyte in Example 69 to Comparative Example F¹ UCH A beta A beta NF-L Tau GFAP L1 40 42 S100B NSE 0.9-1.1 0.9-1.1 0.9-1.1 0.9-1.1 0.9-1.1 0.9-1.1 0.9-1.1 0.9-1.1 ¹Unspiked samples. Concentration is presented in pg/mL.

TABLE 30 Ratio of Observed to Expected Concentration for Each of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE at different levels of dilution¹ Dilution² Example 70 Comparative Example G Initial 100% 100%  2x 100-115% 120-150%  4x 105-130% 150-180%  8x 110-140% 190-220% 16x 120-150% 210-240% ¹Percentages shown are the percentage ratio of observed concentration to expected concentration. ²Dilution would be relative to initial dilution.

All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby. 

What is claimed is:
 1. A method to test for a suspected neural injury in a subject, comprising: i) eluting a dried sample of physiological fluid in a diluent to form a liquid sample, the physiological fluid obtained from the subject within 24 hours of an occurrence of the suspected neural injury; ii) exposing at least a portion of the liquid sample to a plurality of capture objects, the plurality of capture objects comprising binding surfaces having affinity for one or more biomarkers selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; iii) binding at least one capture object of the plurality of capture objects to at least one molecule of the one or more biomarkers; iv) verifying that a statistically significant proportion of the exposed plurality of capture objects are not bound to any of the one or more biomarkers; and v) obtaining one or more concentrations of the one or more biomarkers in the liquid sample.
 2. The method of claim 1, wherein the suspected neural injury is a suspected traumatic brain injury.
 3. The method of claim 2, wherein the suspected neural injury is collateral to childbirth the subject.
 4. The method of claim 1, wherein the dried sample of physiological fluid comprises one or more dried spots of capillary blood.
 5. The method of claim 1, wherein the diluent comprises human IgG at a concentration of between 1 mg/mL and 10 mg/mL.
 6. The method of claim 1, wherein the one or more biomarkers is at least two biomarkers and the obtained one or more concentrations is at least two concentrations, wherein the obtaining comprises: i) calculating at least two measured parameters based on Poisson and/or Gaussian distribution analysis of the exposed plurality of capture objects; and ii) inputting the at least two measured parameters into a multivariate calibration model.
 7. The method of claim 6, wherein the multivariate calibration model is derived from results of a series of multiplex calibration immunoassays.
 8. The method of claim 7, wherein the multivariate calibration model provides a series of comparative concentration values for the at least two biomarkers that are between 80% and 140% proportional when the liquid sample is diluted between 4 times and 64 times with the diluent.
 9. The method of claim 7, wherein at least one of the series of multiplex calibration immunoassays comprises a multiplex assay performed on a calibration solution containing the at least two biomarkers.
 10. The method of claim 6, wherein at least one of the at least two concentrations is indicative of the suspected neural injury at a level of less than 1 picomole/L.
 11. A test for a neurological condition in a subject, comprising: i) providing a liquid sample derived from a sample of dried physiological fluid taken from the subject; ii) obtaining, via a multiplex immunoassay, concentrations of at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the liquid sample; iii) calculating at least one classification value based on a multivariate classification model using the obtained concentrations as inputs to the multivariate classification model; and iv) assigning a risk of the neurological condition, comprising: comparing the at least one classification value to at least one threshold value.
 12. The test of claim 11, wherein the neurological condition is a neurodegenerative disease.
 13. The test of claim 11, wherein the multiplex immunoassay is a digital assay.
 14. The test of claim 11, wherein the multiplex immunoassay is a multiplex spotted well assay.
 15. The test of claim 11, wherein the multivariate classification model predicts the neurological condition with an ROC curve having an AUC of at least 0.85.
 16. The test of claim 11, wherein the multivariate classification model predicts the neurological condition with a true positive rate of at least 75% at a false positive rate of less than 25%.
 17. The test of claim 11, wherein the test further comprises: determining whether a CT scan of the subject is positive or negative for the neurological condition prior to performing the multiplex immunoassay.
 18. The test of claim 11, wherein the at least one classification value comprises a ratio of one of the obtained concentrations to a concentration of a reference component present in the liquid sample.
 19. A multi-sample test for a neurological condition in a subject, comprising: i) providing: a) a first liquid sample derived from a dried sample of a first physiological fluid taken from the subject at a first time; and b) at least a second liquid sample derived from at least a second physiological fluid taken from the subject at least a second time; ii) performing: a) a first multiplex immunoassay to obtain first concentrations of at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the first liquid sample; and b) at least a second multiplex immunoassay to obtain at least second concentrations of the at least two of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE in the at least second liquid sample; and iii) assigning a risk of the neurological condition in the subject, comprising: determining at least one measure of significance of differences between the first concentrations and the at least second concentrations.
 20. The multi-sample test of claim 19, wherein the first time is prior to the at least second time, wherein the at least second physiological fluid is taken in response to a suspected occurrence of the neurological condition.
 21. A kit, comprising: i) a plurality of capture agents configured to separately bind to two or more types of analytes selected from the group consisting of NF-L, GFAP, UCH L1, Tau, A beta 40, A beta 42, S100B, and NSE; ii) a further capture agent configured to selectively bind to reference biomarker, the reference biomarker present in one or more physiological fluids at concentrations that are insensitive to changes in CNS function associated with onset of one or more neurological conditions; iii) a sample diluent, comprising: human IgG at a concentration of between 1 mg/mL and 10 mg/mL; and iv) a plurality of calibration solutions that are pre-diluted for use to determine a calibration standard curve without further dilution, comprising: a) a plurality of predetermined concentrations of the selected two or more types of analytes; and b) a plurality of predetermined concentrations of the reference biomarker. 